WO2008048299A2

WO2008048299A2 - Method of synthesizing nanometer scale objects and devices resulting therefrom

Info

Publication number: WO2008048299A2
Application number: PCT/US2006/045405
Authority: WO
Inventors: Mark L. Jenson
Original assignee: Solumen Corporation
Priority date: 2005-11-22
Filing date: 2006-11-22
Publication date: 2008-04-24
Also published as: WO2008048299A3

Abstract

Methods and devices are described that allow the engineering of a wide variety of nanometer scale objects. These methods and devices use the free energies of materials along with deposition conditions to synthesize a wide array of nanometer scale objects including, but not limited to, particles, quantum dots, clusters or crystals. By appropriate selection of materials and fabrication conditions, the material being deposited on a substrate can be caused to coalesce into islands whose shape and size can be engineered to accomplish a specific desired function. Examples of devices fabricated from this method include, but are not limited to, electronic switching devices, optical switching devices, conjugate formation for biomedical applications, laser and LED applications, power and energy systems and solid state lighting applications.

Description

Method of Synthesizing Nanometer Scale Objects and Devices

Resulting Therefrom

Background of the Invention

1. Field of Invention

This invention relates to the fabrication of nanometer scale objects that are useful in a variety of disciplines including but not limited to electronic switching devices, optical switching devices, conjugate formation for biomedical applications, laser and LED applications, power and energy systems and solid state lighting applications.

2. Description of Related Art

The field of quantum mechanics has experienced remarkable growth over the last few decades as understanding of particle physics has increased. Vastly improved analytical and observation techniques are allowing increased understanding of how materials behave as the structure of the material approaches the limits of "small." New methods of fabrication are being developed based on this increased understanding. It has recently been reported that nanocrystals of Cadmium Selenide (CdSe) synthesized from chemical solution exhibited white light emission upon excitation. (White-Light Emission from Magic-Sized Cadmium Selenide Nanocrystals, Michael J. Bowers II, James R. McBride, and Sandra J. Rosentha,Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235. The process for producing these nanocrystals is further described in Supplementary Information for: White-light Emission from Magic Sized Cadmium Selenide Nanocrystals Michael J. Bowers II, James R. McBride and Sandra J. Rosenthal* Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235.) Such a development may have a dramatic impact on the development of solid state lighting.

In the Vanderbilt method, a 1.0 M solution of selenium in TBP was produced by dissolving 7.896 g selenium powder in 100 niL of TBP. The 0.10 M injection solution was made by dilution of the 1.0 M Se:TBP solution with ODE. The reaction solvent was mixed from a unit quantity of TOPO and HDA (7.2 g and 2.97 g respectively) along with 0.128 g of CdO and 0.496 g of DPA (scaled as necessary). These contents were heated in a 100 mL three neck °ask under argon with vigorous stirring to 310 ⁰C. A needle was placed in the septum to allow for an argon purge until the reaction solution reached 150 ⁰C at which point the reaction vessel was considered water and oxygen free.

Upon reaching reaction temperature (330 ⁰C), 5 mL of the Se:TBP:ODE solution was swiftly injected and the temperature reduced to 270⁰C as quickly as was possible without allowing the temperature to drop below 260 ⁰C. To achieve ultra-small nanocrystals (e.g.< 20 A), a second syringe of toluene (typically 5 mL) was injected to reduce the reaction temperature to < 150⁰C within 2-10 seconds after the initial injection (depending on the desired size).

The problem with this and other wet synthesis methods is that the particles once formed must now be somehow removed from solution and placed in a second solution for application in the device. In this process, the particles often undergo undesirable reactions and changes (oxidation, agglomeration for example) which negatively impact the particles performance in the device. Such negative impacts include loss of efficiency in light to energy or energy to light conversion as well as loss of particle size via agglomeration and thus changes in the desired frequency of emitted light or changes in the material bandgap.

Although chemical synthesis from solution is the most common method of producing nanometer scale particles, there has been some work in the area of dry production of such particles. US Patents Nos. 6,194,237 and 6,855,481 describe two such methods. US Patent No. 6,194,237 entitled "Method for Forming Quantum Dot in Semiconductor Device and a Semiconductor Device Resulting Therefrom" issued to Ki Bum Kim, Tae Sik Yoon and Jang Yeon Kwon on February 27, 2001 describes a technique whereby high temperatures are used to agglomerate a material that has been deposited on an insulating layer in one case and sandwiched between two insulating layers in a second case.

US Patent No. 6,855,481 entitled "Apparatus and a Method for Forming a Pattern Using a Crystal Structure of Material" issued to Ki Bum Kim on February 15, 2005 describes a process whereby a high resolution apparatus such as a Transmission Electron Microscope (TEM) is used to define a mask on a surface that can then be used to define a quantum dot. Further, US Patent No. 6,815,242 entitled "Semiconductor Device and Method of Manufacturing the Same" issued to Kohki Mukai and Hiroshi Ishikawa on November 9, 2004 describes a process whereby the lattice constant of a compound semiconductor substrate is used to define the structure of a second layer whose lattice constant is such that mismatch strains will force island formation of a second material deposited on a first material after the Stranski-Krastanov model of thin film growth. This is also referred to as Pseudo Epitaxial growth since the second film will attempt to conform to the lattice structure of the first. "Lattice constant" refers to the constant distance between unit cells in a crystal lattice. A compound semiconductor is composed of elements from two or more different groups of the chemical periodic table (e.g. (1) Group III (B, Al, Ga, In) and Group V (N, P, As, Sb, Bi) for the compounds AlN, AlP, AlAs, GaN, GaP, GaAs, InP, InAs, InSb, AlInGaP, AlGaAs etc, or (2) the compounds of Group II (Zn, Cd, Hg) and Group VI (O, S, Se, Te) such as ZnS, ZnSe, ZnTe, CdTe, HgTe, CdHgTe). Although Si and Ge are elemental (or element) semiconductors, it's worthwhile to note that some Si-based semiconductors that are formed by two elements from the same group (e.g. SiC and SiGe) are also termed as "Compound Semiconductor" in the literature. "Mismatch strains" refer to strain caused when the lattice of a second material attempts naturally to conform to the lattice of a first material.

The dry methods and the many chemical methods currently in use to form semiconductor devices suffer from a variety of issues including necessitating the use of dangerous chemicals, creation of potentially toxic fumes during manufacture, the presence of undesirable reactive constituents in chemical methods, the need for high temperature (US Pat. No. 6,194,237) which would imperil some substrate materials and the limitation of material selection based solely on crystal structure or material that is not amorphous or the need for expensive and sophisticated techniques such as TEM. Undesirable reactive constituents include the chemicals used to synthesize the desired material but are not necessarily a part of the end product. Undesirable reactive constituents also includes impurities that exist in the chemicals used for synthesis and ambient components such as N2, H20, 02, H and other naturally occurring components of the environment in which the synthesis is occurring. An excellent description of surface energy (γ) and the values of γ for metals are given in "Modeling of Surface Energies of Elemental Crystals" Q Jiang, H M Lu and M Zhao published in J. Phys.: Condens. Matter 16 (2004) 521-530. Figure 1 shows a compilation of surface energy values for a number of elements. In Figure 1 , the elements shown have their corresponding surface energies shown for the 100 crystal plane 100. It is clear that other crystal planes for a particular element have their own corresponding surface energy values. For example, as shown in Figure 1, copper (Cu) has a surface energy in the 100 crystal plane of 2.17. But, it has surface energy in the 111 plane of 1.83 and surface energy in the 110 plane of 2.35. For simplicity, in this description where specific surface energies are referred to, the surface energy is the surface energy of the 100 plane. However, it is to be understood that depending on configuration, the surface energy of other crystal planes may be involved. Also, although Figure 1 shows only surface energy values for elements, it is clear that compounds of elements will have their own unique surface energies. Therefore, when selecting materials based on their respective surface energies, the surface energies of compounds as well as elements may be considered.

In view of the foregoing, there is a need for forming quantum dots, nanocrystals, clusters, particles and other nanometer scale objects in a manufacturing process that is environmentally safe, allows wide latitude of material selection, can be done in a cost effective manner and with commonly available equipment.

Summary of Invention

Methods and devices are described that allow the engineering of a wide variety of nanometer scale objects. These methods and devices use the free energies of materials along with deposition conditions to synthesize a wide array of nanometer scale objects including, but not limited to, particles, quantum dots, clusters or crystals. By appropriate selection of materials and fabrication conditions, the material being deposited on a substrate can be caused to coalesce into islands whose shape and size can be engineered to accomplish a specific desired function. Examples of devices fabricated from this method include, but are not limited to, electronic switching devices, optical switching devices, conjugate formation for biomedical applications, laser and LED applications, power and energy systems such as solar panels and solid state lighting applications. The methods and devices of the present invention allow nanometer scale objects to be formed without the problems associated with currently available methods.

The effect of surface energy differences between materials is used to create or engineer structures at the nanometer scale. For example, as shown in Figures 2 and 3, a substrate is created having a high surface energy material deposited on it whose surface free energy is relatively high. The surface free energy of a material is defined as the energy that it takes to make another material adhere to the lattice of the high surface energy material. Tantalum is a good example of this high surface energy material having a surface energy of 4.05γ in the 100 crystal plane. Thereafter, a low surface energy material with a comparatively low surface energy is deposited on the high surface energy material. Silicon is a good example of a candidate for this low surface energy material having a surface free energy of 1.06γ. This process results in the formation of islands of the low surface energy material on the high surface energy material because of a fundamental physical phenomenon of surface physics which dictates that an equilibrium state between the high surface energy material and the low surface energy material will always be achieved. If the high surface energy material and low surface energy material have large differences in this equilibrium potential (surface free energy) then the equilibrium state of the low surface energy material will not be dictated by the equilibrium potential of the high surface energy material. This means that the low surface energy material will form a crystal, or quantum dot or other equilibrium structure that is not related to the structure of the high surface energy material. By correct selection of the high surface energy material and low surface energy materials and fabrication parameters such as rate of deposition, temperature of the substrate and incident energy of the materials being deposited, the size and structure of the islands of low surface energy material is beneficially controlled.

It is therefore an object of the present invention in one or more embodiments to

provide a method for creating islands of a chosen material on a substrate whose shape

and size can be engineered to accomplish a specific desired function.

and size can be engineered to accomplish a specific desired function using dry

techniques.

provide a device using islands of chosen material on a substrate whose shape and size has

been engineered to accomplish a specific desired function.

Not all of these objects need be present in a single embodiment. Instead, a particular embodiment may have one or more of these objects. Further, additional

objects and advantages of the invention besides those presented above may be present in

the present invention. These and other objects of the invention will be clear from the

following detailed description of the invention in connection with the drawings.

The invention will be described hereafter in detail with particular reference to the drawings. Throughout this description, like elements, in whatever embodiment described, refer to common elements wherever referred to and referenced by the same reference number. The characteristics, attributes, functions, interrelations ascribed to a particular element in one location apply to that element when referred to by the same reference number in another location unless specifically stated otherwise.

Brief Description of the Drawings

Figure 1 is a table listing the surface free energies for many elements. Figure 2 is a schematic view of one example of Vollmer- Weber growth. Figure 3 is a schematic view of another example of Vollmer- Weber growth. Figure 4 is a flow chart of the process of one embodiment of the present invention.

Figure 5 is a side schematic view of the layers of material of one embodiment of the present invention shown in Figure 6.

Figure 6 is a side schematic view of the structure of the embodiment of the Figure 5.

Figure 7 is a side schematic view of one embodiment of the invention in the form of a device to emit light. Figure 8 is a side schematic view of another embodiment of the present invention in the form of a solid state light emitting device shown in Figure 7.

Figure 9 is a side schematic view of one embodiment of the present invention to emit light by light excitation. Figure 10 is a side schematic view of the structure of the embodiment of the

Figure 9.

Figure 11 is a side schematic view of one embodiment of the present invention to emit light by light excitation.

Figure 12 is a side schematic view of the structure of the embodiment of the Figure 11.

Figure 13 is a side schematic view of one embodiment of the present invention to emit light by light excitation.

Figure 14 is a side schematic view of the structure of the embodiment of the Figure 13. Figure 15 is a side schematic view of one embodiment of the present invention to emit light by light excitation.

Figure 16 is a side schematic view of the structure of the embodiment of the Figure 15.

Figure 17 is a plan schematic view of an architectural panel embodiment of the invention incorporating the solid state light emitting devices of Figures 9 - 16 or 19 - 29.

Figure 18 is a side schematic view of one embodiment of the present invention to emit light by electrical excitation. Figure 19 is a side schematic view of the structure of the embodiment of the Figure 18.

Figure 20 is a top schematic view of the structure of the embodiment of the Figure 18. Figure 21 is a side schematic view of one embodiment of the present invention to emit light by electrical excitation.

Figure 22 is a side schematic view of the structure of the embodiment of the Figure 21.

Figure 23 is a top schematic view of the structure of the embodiment of the Figure 21.

Figure 24 is a side schematic view of one embodiment of the present invention to emit light by electrical excitation.

Figure 25 is a side schematic view of the structure of the embodiment of the Figure 24. Figure 26 is a top schematic view of the structure of the embodiment of the

Figure 24.

Figure 27 is a side schematic view of an optical switching device embodiment of the invention.

Figure 28 is a side schematic view of the structure of the embodiment of the Figure 27.

Figure 29 is a top schematic view of the structure of the embodiment of the Figure 27. Figures 30, 32, 34, 36 and 38 are side schematic views and Figures 31, 33, 35, 37 and 39 are top schematic views, respectively, of steps in a process to create and a resulting embodiment of a ultra high definition display of the invention.

Figures 40 - 41 are a side schematic and a top schematic view, respectively, of an alternate embodiment of an ultra high definition display of the invention.

Figure 42 is a side schematic view of an embodiment of the invention for use in conjugate formation.

Figure 43 is a perspective schematic view of an embodiment of the invention for use in using solar energy to create electricity. Figure 44 is a side schematic view of the invention of Figure 43.

Detailed Description of the Invention

One aspect of the invention is several methods for forming nanometer scale objects 2 on a substrate 4. Another aspect of the invention is the disclosure of devices incorporating various applications of these nanometer scale objects 2. Examples of the nanometer scale objects 2 include, but are not limited to, quantum dots, clusters and crystals.

The substrate 4 is any exposed surface onto which a first layer 6 of a high surface energy material 8 may be deposited. The substrate 4 may include previously deposited materials that may or may not have been previously dimensioned or patterned for purposes of defining a device. The term substrate 4 includes, but is not limited to, semiconductor wafers, foils, metal, plastic, glasses, fibers, ceramics, or any other material on to which nanometer scale objects 2 are to be deposited. The function of the substrate

I l 4 is to provide a base for the application of the materials described hereafter. Consequently, any material in addition to those listed that performs this function may be used as a substrate 4 and is within the scope of the present invention. The function of the high surface energy material 8 is to provide a material with a relatively high surface energy.

Examples of the high surface energy material 8 include, but are not limited to, to tantalum, tungsten, molybdenum, vanadium or any material listed in the table of Figure 1 or found elsewhere with sufficient energy to cause a subsequent material to form islands on the high surface energy material 8 based on surface free energy differences as described earlier. Consequently, any material in addition to those listed that forms this function may be used as a high surface energy material 8 and is within the scope of the present invention.

Examples of the low surface energy material 10 include, but are not limited to, to indium arsenide (InAs), Cadmium Selenide (CdSe), Si, CdS, GaN, AlGaN, InGaN, AlP, AlAs, AlSb, GaSb, InN, AlN, InSb, InP, MoS2, TiO2, gold sulfide and silica or any material listed in the table of Figure 1 or found elsewhere with sufficient low surface energy to form islands on the high surface energy material 8 based on surface free energy differences as described earlier. Consequently, any material in addition to those listed that forms this function may be used as a low surface energy material 10 and is within the scope of the present invention.

The term deposition means any form of dry (as opposed to wet or chemically derived) deposition. Examples of vacuum deposition techniques include, but are not limited to, evaporation including thermal and electron beam, sputtering including DC and RF, CVD, PECVD, MBE, PLD, thermal spraying and vacuum arc. Examples of atmospheric forming techniques include, but are not limited to, aerosol pyrolysis and atmospheric CVD. Methods also exist to control the energy of the deposition process. Such methods include, but are not limited to, IAD, RF and DC substrate bias, substrate heat, and photon radiation. These methods of depositing material are performed by devices, including, but not limited to, a RF magnetron, a DC magnetron, an electron gun, an evaporation source, an IBD source, a CVD source, a RF diode source, a PLD source, a PECVD source, a LPCVD source, a MBE source, a thermal spraying source, a laser ablation source, a physical vapor deposition source, a chemical vapor deposition source, an atmospheric CVD source, an aerosol pyrolosis source, a cathodic arc source and an anodic arc source. Other forms of deposition and control of the deposition process may also be used so long as a dry layer or first layer 6 of high surface energy material 8 is produced on the substrate 4. A dry layer or first layer 6 means is a layer of high surface energy material 8 having a sufficient thickness that the high surface energy material 8 will be essentially continuous throughout the first layer 6. The function of deposition is to provide an essentially continuous layer of the high surface energy material 8. Consequently, any method of achieving this function may be used and is within the scope of the present invention.

The term adatom used herein means a particle, molecule, atom or ion of material that has not yet been incorporated into the first layer 6.

Figure 4 depicts the steps to create, Figure 5 depicts the layers of and Figure 6 depicts a resulting structure of one embodiment of the present invention. A substrate 4 is provided (Figure 4: step 100) according to any of the techniques described above. The substrate 4 is first properly cleaned. Cleaning methods may include, but are not limited to, solvent, chemical and plasma cleaning. The substrate 4 is placed in a vessel suitable for the deposition of the nanometer scale objects 2. Such vessels may include, but are not limited to, vacuum vessels and controlled atmosphere vessels. A high surface energy material 8, as described above, is then added to the substrate 4 to produce a first layer 6 (Figure 4: step 102). As stated above, this high surface energy material 8 is chosen so that the surface free energy (γ) is suitable to cause the low surface energy material 10 to "ball up" or form islands rather than a continuous layer on the first layer 6. As will be described hereafter, in certain embodiments the high surface energy material 8 is also chosen so that at the thickness of interest (the thickness of interest being the thickness at which the high surface energy material 8 will be essentially continuous), the high surface energy material 8 remains essentially transparent to the frequency of either incident radiation 12 or the "to be" emitted radiation 14. Thereafter, a low surface energy material 10 is added to the first layer 6 in a second layer 16 (Figure 4: step 104). The high surface energy material 8 and low surface energy material 10 may be repeated "n" cycles in layers as desired. The differences in surface energies between the high surface energy material 8 and low surface energy material 10 will cause the low surface energy material 10 to "ball up" or form island structures on the first layer 6 (Figure 4: step 106) after the theory of Vollmer- Weber (Figs. 2 and 3). The equilibrium condition between the high surface energy material 8 and the low surface energy material 10 favors the formation of the dot. In other words, if the surface energy of the high surface energy material 8 is sufficiently large compared to the surface energy of the low surface energy material 10, the low surface energy material 10 will prefer to "ball up" or form islands of itself rather than "spreading out" on the high surface energy material 8 in a layer. If a particular set of conditions produces surface energies of the high surface energy material 8 and low surface energy material 10 that do not produce the desired characteristics or parameters, changing the surface conditions of either the high surface energy material 8 or low surface energy material 10 or both will produce different characteristics or parameters. Manipulating the surface conditions of either the high surface energy material 8 or low surface energy material 10 or both will then produce the desired characteristics or parameters.

Any high surface energy material 8 with sufficiently high surface energy (γ) relative to the low surface energy material 10 and exhibiting the desired electronic, chemical, optical, biological or other properties for the device in question will suffice. Device function will dictate which materials are best suited as the high surface energy material 8 and low surface energy material 10. As a result, the intended end use of the device will dictate the corresponding electronic, chemical, optical, biological or other properties. The list of possible high surface energy material 8 and low surface energy material 10 that can be used is limited only by the functionality desired by the engineer and the ability of the high surface energy material 8 and low surface energy material 10 to withstand the forming environment. Therefore this invention discloses a method of formation for nanometer scale objects 2 whereby the engineer has the freedom of a dry process without necessitating the use of crystalline high surface energy material 8 with their concomitant restrictive materials requirement, high temperature or elaborate and expensive patterning techniques. In the method of the present invention, the engineer selects a high surface energy material 8 of interest, amorphous or crystalline, based on surface free energy and engineers the deposition sequence and the low surface energy material 10 and conditions of deposition to achieve island formation based on the Vollmer- Weber growth model. In cases where one cannot find a high surface energy material 8 that has all of the required physical parameters (surface free energy and electrical qualities for example), the effective surface free energy of either the substrate 4 or deposited high surface energy material 8 can be altered by use of ion assisted deposition, heat or biasing of the substrate 4 or target material (where target material is the source of the material from which the deposited material is derived e.g., tantalum would be deposited from a tantalum target). For example, in a method for producing a quantum dot transistor from nanometer scale objects 2, the substrate 4 may be gallium arsenide (GaAs). In this example of the invention, a thin layer (5 A to 1000 A) of tantalum is deposited on the substrate 4 to form a first layer 6 having a very high surface energy. According to the table of Figure 1, the surface energy of tantalum is approximately 4.05 (Jm^"2). A low surface energy material 10 exhibiting the characteristics for quantum dot transistors such as indium arsenide (InAs) is then deposited on the first layer 6 by any of the deposition techniques mentioned above to produce a second layer 16. By utilizing the deposition techniques mentioned and tailoring the deposition time and system energy (by controlling the electrical bias, heat of the substrate 4 and delivery of energized particles as will be described hereafter), the deposited low surface energy material 10 will "ball up" or form islands according to the theory of Vollmer- Weber as shown in Figs. 2 and 3.

The size of the islands, and consequently the size of the active area of the quantum dot transistor, will be determined by the difference in surface free energy between the first layer 6 on the substrate 4 (in this case, GaAs) and the deposited low surface energy material 10 (in this case, InAs), the thickness of the deposited low surface energy material 10 (as measured on an independent witness slide which is a common method of recording thickness as will occur to those skilled in the art) and the energy of the deposition process which can be varied (by means previously discussed) and used to alter the effective equilibrium potential (discussed earlier) to engineer a dot size that may not be possible without energy being added to the deposition process.

In this example, if a dot 3θA in diameter is desired, the thickness of the deposited first layer 6 and second layer 16 is preferably varied during the deposition process to achieve such a diameter. The thickness required would have previously been determined experimentally by depositing a variety of thicknesses of first layer 6 and second layer 16, analyzing the size of the dot formed with commonly available equipment (such as SEM, TEM or profilometer) and correlating the first layer 6 and second layer 16 thickness to dot (or crystal or particle) diameter. Typical thicknesses of the first layer 6 are from about 5 A to about lOOOA. Typical thicknesses of the second layer 16 are from about 5 A to about lOOOA. While these examples of typical thicknesses for the first layer 6 and the second layer 16 have been given, these thicknesses are not intended to be limiting but rather exemplary.

In some cases it may be necessary to "add" energy to the deposition process of both the first layer 6 and second layer 16 by way of processes such as adding a secondary ion beam (Figure 7) or by providing an "electrical bias" to the substrate 4 to either attract or repel the incoming adatoms of deposited low surface energy material 10. To maintain quality and functionality of the island or dot formed, the first layer 6 and second layer 16 may then be "passivated" insitu by encasing the exposed first layer 6 and second layer 16 in a passivation layer 18 made of a passivation material 20 (108) that hermetically seals the first layer 6 and second layer 16. Passivation materials 8 for forming the passivation layer 18 are widely known and commonly available and may include, without limitation, nitrides, oxides, glasses or polymers in devices that will not require electroluminescent capabilities. As a result, the passivation material 20 in an electroluminescent device is preferably any material that forms a hole conduction layer (electron blocking layer) such as, but not limited to, ionic conducting glasses, p doped semiconducting materials or polymers such as polycarboxy-polymers, quaternized polyamine-polymers, polysulphato-polymers, polysulpho-polymers or polyvinylphosphonic acid, electron conducting layers such as metals or a dielectric layer. In this example, the passivating layer 20 would need to allow some form of electrical activity between the dot and other layers. Therefore, a totally insulating passivation material 20 would not suffice. In some applications described hereafter, a critical factor determining the efficacy of the passivation layer 16 will be its transparency to the emitted radiation 14 or absorbed incident radiation 12.

In some applications additional passivation may be added by bonding or otherwise adhering an additional passivation material 40 to the device 28. Such additional passivation materials 80 may include, without limitation, glasses, metals or combinations of the passivation materials listed above. In some applications as well, a critical factor determining the efficacy of the additional passivation material 40 will be its transparency to the emitted radiation 14 or absorbed incident radiation 12. The method of preparing the substrate 4, depositing the high surface energy material 8 and low surface energy material 10 and producing a passivation layer 18 described above is the method used to prepare the substrates 2, deposit high surface energy material 8 and low surface energy material 10 and produce a passivation layer 18 in all the embodiments described herein unless specifically stated otherwise.

Another example of how this effect is used as a method to fabricate a useful device is as follows and shown in Figures 5 and 6. Nanometer scale objects 2 of quantum dots or nanocrystals of Cadmium Selenide (CdSe) or both are reported to emit white light if the dots or crystals are smaller than some threshold value. The threshold value is generally understood to be the diameter of the dot so that the outer electron orbit is confined by the diameter of the dot. This quantum confinement occurs when electrons and holes in a semiconductor are restricted in one or more dimensions. A (quantum dot) is confined in all three dimensions, a (quantum wire) is confined in two dimensions, and a (quantum well) is confined in one dimension. That is, quantum confinement occurs when one or more of the dimensions of a nanocrystal is made very small so that it approaches the size of an exciton in bulk crystal, called the Bohr exciton radius. A quantum well is a structure where the height is approximately the Bohr exciton radius while the length and breadth can be large. A quantum wire is a structure where the height and breadth is made small while the length can be long. A quantum dot is a structure where all dimensions are near the Bohr exciton radius, typically a small sphere.

In the research project mentioned above, researchers at Vanderbilt University reported white light emission from nanocrystals of CdSe that were on the order of 15A in diameter. The white light emission was observed when nanocrystals of CdSe were excited by either UV or blue laser light. The CdSe crystals used at Vanderbilt were synthesized from a chemical solution that was heated then cooled at specific rates to obtain the size crystals desired as described in the above referenced paper.

The dry method of the present invention can be used to achieve the same effect without the use of chemicals or the specific cooling rates necessitated by the Vanderbilt chemical method. In this method of the invention, a substrate 4 is coated with a first layer 6 of high surface energy material 8 that is sufficiently high in surface energy. An example of such a high surface energy material 8 is tantalum but it is to be understood that any high surface energy material 8 with sufficiently high surface energy γ will suffice in addition to tantalum such as tungsten, molybdenum or vanadium.

A second film 16 of a low surface energy material 10 is deposited onto the first layer 6 of high surface energy material 8. An example of low surface energy material 10 is CdSe but any low surface energy material 10 which has properties of interest to the end use device and with a sufficient low surface energy so that the newly deposited low surface energy material 10 coalesces into islands, the ability to be dry deposited and having characteristics of interest will do. Si and CdS are other examples of this low surface energy material 10.

The thickness of the deposited low surface energy material 10 along with the thermal energy and incident ion energy will determine the size of the islands (dots) that form. As has been described above, by experimentation the diameter of the dot can be correlated to film thickness of the second layer 16. Additionally, by altering the equilibrium conditions of the system during the deposition process through the addition of energy (e.g., heat, secondary ions, electrical bias) the growth or formation of the "dots" can be further controlled.

By judicious selection of high surface energy material 8 (e.g., tantalum) effects such as pseudo epitaxial growth can be eliminated and ignored. Pseudo epitaxial growth is described as the tendency of a second deposited film (e.g., the second layer 16) to conform to the lattice structure of a first film (e.g, the first layer 6). The large difference in surface energies of the high surface energy material 8 and low surface energy material 10 will overcome any tendency of the low surface energy material 10 to conform to the crystal (lattice) structure of the high surface energy material 8 since equilibrium will favor crystal or dot formation of the low surface energy material 10.

This method can be used to form dots ranging from atoms to thousands of atoms until the islands themselves begin to coalesce into larger structures and the quantum effects are no longer available.

By appropriate preparation of the substrate 4 using masking and etching such as is common to semiconductor processing, one could fabricate gates, grids, wires, etc. of the desired shape size and frequency to achieve the functionality desired. In some cases the desired function may be a single electron gate in an electronic device or a series of patterns for an optical switching device, dye replacement for bioconjugates, solar cell junction or possibly a junction for a light emitting device. Another embodiment of the present invention shown in Figure 7 is a method of depositing films on a substrate to produce a solid state light emitting device 22. This method includes providing a substrate 4, forming a first layer 6 on the substrate 4 of a high surface energy material 8, forming, by deposition, a light emitting second layer 16 on the first layer 6 of a low surface energy material 10 having a lower surface energy than the high surface energy material 8 and preferably supplying energized particles 24 from an energized particles source 26 so that the particles 24 provide energy to the low surface energy material 10 to deposit the low surface energy material 10 into a desired second layer 16 structure and finally forming a passivating layer 7 as described above.

In this embodiment of the invention, the energized particles 24 are preferably ions having energy of between about 3eV and 35OeV. These energized particles 24 act to modify the effective surface energy of the low surface energy material 10 thereby allowing the engineering of the dot formation of low surface energy material 10 on material 8. As a result, the formation and size of the resulting nanometer scale objects 2 is influenced. In this embodiment of the invention, the energized particle source 26 is preferably a ion gun such as a Kauffman type that uses a source gas of oxygen or nitrogen or noble gases such as argon, helium, neon, krypton or xenon. The energized particle source 26 may also use gas that includes a hydrocarbon precursor so that via a chemical vapor deposition methodology, an ultrathin, light layer 16 of the low surface energy material 10 is formed on the surface of the high surface energy high surface energy material 8. This technique of using energized particles 24 may be applied as desired to any embodiment of the invention described herein. Although the preferred embodiment of the solid state light emitting device 22 is made using energized particles 24, these energized particles 24 are not required to be used if the surface energy of the high surface energy material 8 is sufficiently high without using the energized particles 24. Another embodiment of the present invention shown in Figure 10 is a solid state light emitting device 22 produced by another method of depositing films on a substrate 4. In this embodiment of the invention, the light emitting device 22 includes a substrate 4 with a first layer 6 of a high surface energy high surface energy material 8, a light emitting second layer 16 having a thickness of preferably less than 350 Angstroms made of a low surface energy material 10 having a lower surface energy than the high surface energy material 8 and a passivating layer 18. This second layer 16 is described as having a thickness preferably less than 350 Angstroms. However, the thickness of this second layer 16 may be more or less than this keeping in mind that the thickness may impact brightness. Alternately, as described in other embodiments of the invention and as shown in Figure 8, first and second layers 6, 16 are repeated over "n" cycles (three times in the example shown) to provide a light producing structure that has the desired brightness. Using the methods and techniques described above to produce nanometer scale objects 2, several structures and devices, collectively devices 28, are possible. One such category of devices 28, shown in Figures 9 - 16, is light emitting devices 22 excited by incident radiation 12. Incident radiation 12 means radiation such as is visible or invisible to the human eye that impinges on the device 28 from a artificial source such as an LED, incandescent light, florescent light, laser, LCD or plasma discharge or from naturally produced or ambient light. Examples of such structures and devices include, but are not limited to, windows, doors, separators, decorative and architectural panels 84 (Figure 17), construction materials, jewelry, sequins, surfaces, clothing, footwear, utensils, appliances, transportation, luggage, clothing accessories, business accessories, travel accessories, and derivative thereof. Nanometer scale objects 2 capable of producing light in the frequency of interest for these devices 28 are formed on a substrate 4. In these embodiments of the invention, the substrate 4 is prepared and a high surface energy material 8 and low surface energy material 10 deposited and a passivation layer 20 produced as described above. The shape and size of the substrate 4 is dictated only by the end use. In all of these embodiments, the low surface energy material 10 is excited to produce emitted radiation 14 by the incident radiation 12.

The substrate 4 may be transparent to incident radiation 12 but opaque to emitted radiation 14 (Figures 9 and 10), transparent to incident radiation 12 and emitted radiation 14 (Figures 11 and 12), opaque to incident radiation 12 but transparent to emitted radiation 14 (Figures 13 and 14) or opaque to both incident radiation 12 and emitted radiation 14 (Figures 15 and 16). The required transparency of the substrate 4 is dependent on either the frequency of the incident radiation 12 or the frequency of the emitted radiation 14 from the device 28. The frequency of the incident radiation 12 may be broad or narrow spectrum. Examples of narrow spectrum excitation energies include those producing UV, red, green and blue light. Examples of broad spectrum excitation energies include those producing blue, white and natural light.

Where either the incident radiation 12 or the emitted radiation 14 is to pass through the substrate 4, the material of the substrate 4 may be glass, plastic or other broad spectrum transparent material. Where the substrate 4 is transparent to either incident radiation 12 or emitted radiation 14 or both, the incident radiation 12 or incident radiation 14 may pass through the substrate 4 from the ambient light or from the low surface energy material 10, respectively. Where the substrate 4 is transparent to incident radiation 12, the incident radiation 12 could enter the device 28 from virtually all directions including through the substrate 4 but generally is understood to come from a predetermined source. Where the substrate 4 is transparent to emitted radiation 14, the emitted radiation 14 emitted from the low surface energy material 10 leaves the device 28 in virtually all directions including through the substrate 4 but generally is directed in a direction by the use of reflective surfaces and or lenses. An illustrative example of a device 28 embodying the nanoscale particles 2 formed as described above is the panel 84 shown in Figure 17.

Another category of embodiments of the invention are light emitting devices excited electrically, collectively devices 30. Examples of devices 30 include, but are not limited to, windows, doors, separators, decorative and architectural panels, electronic displays, electronic screens, construction materials, jewelry, sequins, surfaces, clothing, footwear, utensils, appliances, transportation, luggage, clothing accessories, business accessories, travel accessories, and derivative thereof. In this embodiment, nanometer scale particles 2 capable of producing light in the frequency of interest are formed on any substrate 4 of interest to the end use. Such substrates include, but are not limited to, glasses, plastics, textiles, semiconducting materials, active devices, passive devices, metals, rigid materials, flexible materials or any other material that has a desired end use and can withstand the deposition conditions required by this disclosure. The substrate 4 material must be glass, plastic or other broad spectrum transparent materials if the device 30 is built such that the emitted radiation 14 is to pass through this substrate 4.

An embodiment of a device 30 built such that the emitted radiation 14 passes through the substrate 4 is described as follows and is shown as Figures 18 - 20. A substrate 4 is chosen that will be essentially transparent to the emitted radiation 14. In one embodiment, the emitted radiation 14 may be broadband white light although emitted radiation 14 of other frequencies is also within the scope of the invention. In this embodiment, most glass and plastic substrates 2 would be a good choice. The shape and size of the substrate 4 is dictated only by the end use.

In this embodiment of the invention, the substrate 4 is prepared as described above. A high surface energy material 8 is deposited on the substrate 4 by means previously noted. The high surface energy material 8 is also chosen such that at the thickness of interest it remains essentially transparent to the frequency of the "to be" emitted radiation 14. The high surface energy material 8 is also chosen such that it creates an appropriate junction 36 with respect to a source of electrical energy 32. Again, the high surface energy material 8 is chosen such that the surface free energy (γ) is suitable to cause the low surface energy material 10 to "ball up" or form islands rather than a continuous layer. A low surface energy material 10 is then deposited by means previously noted.

This low surface energy material 10 is the material that will emit light once properly electrically excited. The high surface energy material 8 and low surface energy material 10 may be repeated "n" cycles to increase the lumen yield of the device. Once adequate cycles of the materials have been deposited, an isolating material 34 is deposited which acts to isolate the underlying materials from an electrically conducting material 42 while allowing the transport of holes but not electrons.

An electrically conducting material 42 is supplied to the substrate 4 which connects the materials of the device 30 to a source of electrical energy 32. The electrically conducting material 42 is chosen such that it creates an appropriate junction 38 with respect to a source of electrical energy 32. The source of electrical energy 32 is used to excite the high surface energy material 8 and electrically conducting material 42 creating a potential which when overcome allow the beneficial recombination of electrons and holes in the emissive low surface energy material 10 which causes emitted radiation 14 to be emitted.

In some cases the source of electrical energy 32 is an external source such as a battery, integrated circuit or power supply powered by conventional commercial AC electricity. In other cases the source of electrical energy 32 is supplied by additional engineering (previous or subsequent) of the substrate 4 such as the addition of integrated circuits to the device 30 or the inclusion of on board power sources such as solid state batteries.

Optionally a passivation material 20 may be added that acts to passivate the underlying layers from atmospheric and other undesired outside influences as described above. In the case of a flexible plastic or glass substrate, the passivating material 20 must be sufficiently flexible to allow flexure without loss of hermetic seal within the confines of normal use. In some applications additional passivation material 40 may be added by bonding or otherwise adhering to the passivation material 20 of the device 30.

An embodiment of a device 30 built such that the emitted radiation 14 does not pass through the substrate 4 is described as follows and is shown as Figures 21 - 23. A substrate 4 is chosen that has the required characteristics for the end product. Such substrates 2 include, without limitation, glasses, plastics, textiles, semiconducting materials, active devices, passive devices, metals, rigid materials, flexible materials, or any other material that has a desired end use and can withstand the deposition conditions required by this disclosure. The shape and size of the substrate 4 is again dictated only by the end use. The substrate 4 is prepared as described above. An electrically conducting material 42 is deposited on the substrate 4 by means previously noted. An electrically conducting material 42 is supplied to the substrate 4 which acts to electrically connect the device 30 to a source of energy 32 through a junction 38 (in conjunction with the high surface energy material 8 through a junction 36). The source of electrical energy 32 is used to excite the junction 38 between the electrically conducting material 42 and the high surface energy material 8 creating a potential which, when overcome, allows the beneficial recombination of electrons and holes in the emissive low surface energy material 10 which causes emitted radiation 14 to be emitted.

The electrically conducting material 42 is deposited on the substrate 4 by means previously noted. An isolating material 34 is deposited next which acts to isolate the electrically conducting material 42 from the subsequent materials while allowing the transport of holes but not electrons. A high surface energy material 8 is deposited next. The high surface energy material 8 is chosen so that the surface free energy (γ) is suitable to cause the low surface energy material 10 to "ball up" or form islands rather than a continuous layer. The high surface energy material 8 is also chosen such that at the thickness of interest it remains essentially transparent to the frequency of the "to be" emitted radiation 14. The high surface energy material 8 is also preferably chosen so that it creates the appropriate junction 36 described above to electrically connect the junction 36, and thereby the high surface energy material 8, to the source of electrical energy 32 at a point opposite in polarity to the electrically conducting material 42. A low surface energy material 10 is then deposited by means previously noted. This low surface energy material 10 is the material that will emit light (emitted radiation 14) once properly electrically excited. The high surface energy material 8 and low surface energy material 10 may be repeated "n" cycles to increase the lumen yield of the device 30.

If the high surface energy material 8 chosen, whether alone or as part of a stack of "n" layers of high surface energy material 8 and low surface energy material 10, does not provide adequate electrical conductivity to the source of electrical energy 32 through a junction 36, a second electrically conducting material 44 may need to be deposited to provide the electrical connection (junction 36) to the source of electrical energy 32. The second electrically conducting material 44 may be added to other embodiments of the invention that are connected to a source of electrical energy 32 or a load 60 where the high surface energy material 8 chosen does not provide adequate electrical conductivity to the source of electrical energy 32 or load 60. In this embodiment, this second electrically conducting material 44, if used, is deposited between the low surface energy material 10 and a passivation material 20. An additional requirement of this optional second electrically conducting material 44 in this embodiment is the need to be transparent at the emitted radiation 14 frequency.

A passivation material 20, as described above, is deposited which acts to passivate the underlying materials from unwanted external effects yet is essentially transparent to the frequency of the emitted light 14 from the device 30. A critical factor determining the efficacy of any passivation material 20 that may be used is its transparency to the emitted radiation 14. An alternate embodiment of a device 30 built such that the emitted radiation 14 does not pass through the substrate 4 is described as follows and is shown as Figures 24 - 26. This embodiment is exactly like the embodiment described above and shown in Figures 21 — 23 except that the second electrically conducting material 44, if used, is deposited between the high surface energy material 8 and the low surface energy material 10 to create the junction 36.

Another category of embodiments of the invention are Electrical to Optical switching devices 46. Examples of devices 46 include, but are not limited to fiber optic components, electronic circuits including logic, data transmission, video transmission, guardian circuits, control circuits and derivatives thereof. Nanometer scale particles 2 are used in the conversion of electrical signals to light pulses and conversely for converting light pulses to electrical signals. Light is well known to travel great distances without the RC losses typical in electrical signals. The primary difference between this application of the disclosed technology and applications for production of general illumination is simply a matter of scale. In this case, the scale is measured in microns to centimeters and does not have the intended purpose of producing a light quality suitable for illumination.

An embodiment where an electrical signal is desired to be converted to a light pulse is described as follows and is shown as Figures 27 - 29. An electrical signal is brought to a header 52. The header 52 may be as small as a transistor or as large as is necessary for the desired end use. The function of the header 52 is to functionally interface the electrical signal to the optical switching device 46.

An electrical signal is fed into the electrical to optical switching device 46 (via header 52) which has had the appropriate materials fabricated on it. An example of such a fabrication sequence is as follows. The shape and size of the device 46 is dictated only by the end use.

The preparation of header 52 is not a part of this disclosure and is simply descriptive of the need to functionally connect some outside electrical signal to this optical switching device. The shape and size of the header 52 is dictated only by the end use. An electrically conducting material 42 is supplied to the header 52 which acts to electrically connect the device 46 (in conjunction with a third or second electrically conducting material 44) to a source of electrical energy 32 which will be used to excite a junction 38 between the electrically conducting material 42 and high surface energy material 8 or second electrically conducting material 44 creating a potential which when overcome allow the beneficial recombination of electrons and holes in the emissive low surface energy material 10 to emit emitted radiation 14. The source of electrical energy 32 is as described above.

The electrically conducting material 42 is deposited on the header 52 by means previously noted. An isolating material 34 is deposited next which acts to isolate the electrically conducting material 42 from the subsequent materials while allowing the transport of holes but not electrons. A high surface energy material 8 is deposited next. The high surface energy material 8 is chosen such that the surface free energy (γ) is suitable to cause the low surface energy material 10 to "ball up" or form islands rather than a continuous layer. The high surface energy material 8 is also chosen so that at the thickness of interest, it remains essentially transparent to the frequency of the "to be" emitted radiation 14. The high surface energy material 8 is also preferably chosen so that it creates the appropriate junction 36 to electrically connect the device 46 to a source of electrical energy 32 at a point opposite in polarity to the electrically conducting material 42.

A low surface energy material 10 is then deposited by means previously noted. This low surface energy material 10 is the material that will emit light (emitted radiation 14) once properly electrically excited. The high surface energy material 8 and low surface energy material 10 may be repeated "n" cycles to increase the lumen yield of the device 46. Once adequate cycles of the high surface energy material 8 and low surface energy material 10 have been deposited and if the high surface energy material 8 chosen does not provide adequate electrical conductivity, a second electrically conducting material 44 may need to be deposited between the low surface energy material 10 and a passivation material 20 to provide electrical connection to the source of electrical energy 32 through a junction 36. An additional requirement of this optional second electrically conducting material 44 layer is its need to be transparent at the emitted radiation 14 frequency. A passivation material 20 as described above is next deposited which acts to passivate the underlying materials from unwanted external effects yet is essentially transparent to the frequency of the light to be emitted by the device. In some applications additional passivation material 40, as described above, may be added where a critical factor in determining the efficacy of the additional passivation material 40 will be its transparency to the emitted radiation 14. The emitted radiation 14 is collected and fed to an appropriate transport mechanism such as optical fiber by techniques well understood in the art. Conversion of the light pulse back to an electrical signal is accomplished by using PV methods. Another category of embodiments of the invention are Ultra High Definition Displays 48. Examples of Ultra High Definition Displays include, but are not limited to, military displays, heads up displays, avionics displays, aerospace displays, vision implants, commercial displays including telephone, electronics devices, television, computers, and personal electronics devices, automotive displays, industrial displays, medical displays, medical instruments, invasive medical instruments, toys, games, video displays, data displays, microscope displays, analytical instrument displays, tagging displays, control displays, security displays, and derivatives thereof. It is believed Ultra High Definition Displays 48 of the present invention could have many applications in both the defense and commercial markets.

In this embodiment, nanometer scale particles 2 are engineered to produce red, green or blue outputs. It is also believed it is possible to engineer nanometer scale particles 2 that can produce any color desired by simple voltage control thus alleviating the need for RGB mixing. Since no phosphors are needed, the longevity and switching speed of the Ultra High Definition Display 48 can be much higher than is available using traditional means. The lack of persistence in the video output is not an issue since the color will stay in place as long as an electrical signal is present. Extremely thin yet rugged Ultra High Definition Displays 48 are possible with this invention.

Embodiments of an Ultra High Definition Display 48 built such that the emitted radiation 14 passes through the substrate 4 is as follows and is shown in Figures 30 - 29. A substrate 4 is chosen that will be essentially transparent to the emitted radiation 14. In one embodiment, the emitted radiation 14 is red, green or blue light while in another embodiment the emitted radiation 14 is broadband white light. In these embodiments, most glass and plastic substrates 2 would be a good choice. The shape and size of the substrate 4 is dictated only by the end use. The substrate 4 is prepared as described above.

A high surface energy material 8 is deposited on the substrate 4 by means previously noted. The high surface energy material 8 is also chosen such that at the thickness of interest it remains essentially transparent to the frequency of the "to be" emitted radiation 14. The high surface energy material 8 is also preferably chosen so that it creates the appropriate junction 36 with respect to the source of electrical energy 32 as described above and is electrically connected to the source of electrical energy 32 through the junction 36. Again, the high surface energy material 8 is chosen so that the surface free energy (γ) is suitable to cause the low surface energy material 10 to "ball up" or form islands rather than a continuous layer.

A low surface energy material 10 is then deposited by means previously noted. This low surface energy material 10 is the material that will emit light (emitted radiation 14) once properly electrically excited. The high surface energy material 8 and low surface energy material 10 (or second electrically conducting material 44 and low surface energy material 10) may be repeated "n" cycles to increase the lumen yield of the Ultra High Definition Display 48.

Once adequate cycles of the materials have been deposited, an isolating material 34 is deposited which acts to isolate the underlying materials from an electrically conducting material 42 while allowing the transport of holes but not electrons. An electrically conducting material 42 is applied next which, along with the high surface energy material 8 as described above, acts to electrically connect the Ultra High Definition Display 48 to a source of electrical energy 32. The source of electrical energy 32 will excite the junction 36 and junction 38 creating a potential which, when overcome, allows the beneficial recombination of electrons and holes in the emissive low surface energy material 10 with the resulting emitting of emitted radiation 14. The source of electrical energy 32 is as described above. Optionally a passivation material 20, as described above, may be added that acts to passivate the underlying layers from atmospheric and other undesired outside influences. In some applications additional passivation material 40 as described above may be added.

In the method shown in Figures 30 - 39, the pixels 72 a of Ultra High Definition Display 48 are defined by etching. This is accomplished as follows. Layers of high surface energy material 8, low surface energy material 10, isolating material 34, electrically conducting material 42 and passivation material 20 or additional passivation material 40, if used, are placed on a substrate 4 as described above to collectively form material 80. (Figures 30 and 3I) A first pattern material 74 is applied opposite the substrate 4 to the material 80. (Figures 32 and 33) The first pattern material 74 has a width that, combined with the second pattern material 76 described below, defines the location and width of the pixels 72 in one dimension and will protect the underlying material during the etching process. Etching is then done by chemical means, laser ablation or other well known and understood etching means all as is well understood in the art. As a result, the material 80 under the first pattern material 74 is preserved during the etching process. (Figures 34 and 35)

Second pattern material 76 is applied next which has a width that in combination with the first pattern material 74 defines the height and consequently the size and location of the individual pixels 72. (Figures 36 and 37) The second pattern material 76 is preferably, although not required to be, applied at right angles to the first pattern material 74. The second pattern material 76 will also protect the underlying material during the etching process. Etching is then done by chemical means or laser ablation or other etching means as is well understood in the art. As a result, the material 82 under the second pattern material 76, including the material originally under the first pattern material 74, is preserved during the etching process. (Figures 38 and 39) This material that is preserved under both the first pattern material 74 and the second pattern material 76 is the pixels 72. Once pixels 72 are formed, additional wiring is added to the device to allow connection to a source of electrical energy. Individual pixels 72 are addressed in a method identical to methods in common use today and well understood in the art in solid state memory and flat panel displays.

In another embodiment, the definition of pixels 72 of a Ultra High Definition Display 48 is accomplished by the method shown in Figures 40 and 41. Figure 40 shows layers of the high surface energy material 8, low surface energy material 10, isolating material 34, electrically conducting material 42 and passivation material 20 prepared as described above. Figure 41 shows the material of Figure 40 with material removed by etching, for example as described above. Pixels 72 are formed at the junction of material 8 and electrically conducting material 42. Individual pixels 72 are addressed in a method identical to methods in common use today and well understood in the art in solid state memory and flat panel displays.

Another category of embodiments of the invention are Bioconjugate Formation devices 50. Examples of bioconjugate formation devices 50 include, but are not limited to, bio sensing, bio imaging, markers, masking, tags, insitu probes, fluorescent labels, targeted drug delivery, photo thermally triggered devices, colorimetric assays, and derivates thereof.

Bioconjugates are used in research, diagnostics, and therapeutics in medical applications. For most applications, the typical synthesis of the bioconjugates is carried out using traditional wet chemical methods. There are applications however where the purity of the bioconjugate is vastly improved if the materials is not exposed to chemical or atmospheric constituents prior to incorporation. This invention allows the formation of extremely pure bioconjugates for use in applications where conjugate purity is critical to mission success.

A typical embodiment for a conjugate formation useful as a fluorescent biological label is described as follows and is shown in Figure 42. Doping of nanometer scale objects 2 as shown in Figure 42 can also be achieved using the methods of this invention. If a CdSe low surface energy material 15 was to be doped with manganese (Mn), one could simply deposit the Mn material 10 on the tantalum high surface energy material 8 with the requisite fabrication parameters to affect the size particle (sphere) desired, and then follow this deposition with the CdSe low surface energy material 15. The physical forces (surface free energy) at play on the surface (tantalum and the Mn spheres) would favor CdSe coating of the Mn spheres. The end result is a CdSe coated Mn sphere on the high surface energy material 8.

A releasable substrate 4 is used to act as a base for the formation of the conjugate. The material chosen for the substrate 4 should be one with a high surface energy such as teflon or other such material. Other material selections are also possible for substrate 4 so long as one can accomplish a release of subsequent materials deposited on substrate 4 by means that are not destructive to the deposited material. Such release may include, without limitation, UV exposure, solvent exposure and acid exposure.

A low surface energy material 10 such a Mn is deposited onto the substrate 4 by means previously described. This low surface energy material 10 will be the core material. Materials of interest for the low surface energy material 10 include, but are not limited to, gold sulfide, silica, cadmium sulfide although many others may also be used. By controlling the size of the core material, the overall conjugate size may be beneficially controlled which may in turn control the response of the conjugate to IR or other stimulus or query. The low surface energy material 10 will ball up on the high surface energy substrate 4 resulting in the formation of nanometer scale particles 2. Follow this deposition with the CdSe low surface energy material 15. The physical forces (surface free energy) at play on the surface (tantalum and the Mn spheres) would favor CdSe coating of the Mn spheres. As a result, a CdSe coated Mn sphere is formed on the high surface energy material 8. Once the conjugate material is formed, the material may be released from the substrate 4 by a variety of means including scraping, heating, etching, UV, solvents, acids or electrostatic release.

Another category of embodiments of the invention are solar energy devices 54. Examples of solar energy devices 54 include, but are not limited to, photovoltaic energy conversion devices, solar cells and solar panels.

Solar energy conversion devices are often fabricated using semiconducting materials including nanocrystals. Typical methods of forming semiconducting nanocyrstals include the use of wet synthesis to form nanocrystals of CdSe and PbSe. Although low cost in approach, this method results in low efficiency nanocrystals due to undersirable reactions that take place within and on the surface of the nanocrystal as the material is moved from the fabrication solution or chemical to a second solution or chemical used in application of the nanocrystal to a device. Also, an undesirable agglomeration of the nanocrystals can occur in this transfer process resulting in loss of performance by increase of the nanocrystal effective diameter.

An embodiment of the solar energy devices 54 that makes use of the present invention is described as follows and is shown in Figures 43 and 44. In this embodiment, a substrate 4 is chosen that will be essentially transparent to the ambient incident radiation 12. In the preferred embodiment, the incident radiation 12 is sunlight. In this embodiment, most glass and plastic substrates 2 would be a good choice. The shape and size of the substrate 4 is dictated only by the end use. The method of preparing the substrate 4 described above is the method used to prepare the substrates 2.

An antireflective material 56 is supplied to the substrate 4. The antireflective material 56 acts to provide an anti reflective coating to the solar energy device 54 allowing the maximum amount of incident radiation 12 capture by the solar energy device 54. A contact grid material 58 is then applied to the antireflective material 56 which acts to electrically connect the solar energy device 54 to a load 60.

A first semiconducting material 62 is then supplied to the contact grid material 58. The first semiconducting material 62 is a P-doped semiconducting material. An example of this first semiconducting material 62 is boron doped silicon.

A high surface energy material 8 having high surface energy such as tantalum is then supplied to the first semiconducting material 62. The high surface energy material 8 acts to form a high surface energy base for the subsequent material after the teaching of this patent. This high surface energy material 8 must be a continuous film but thin enough to be essentially transparent to the incident light 12. The typical thickness of the high surface energy material 8 would be about 5 Angstroms to about 1000 Angstroms. An electron emitting material 64 is then deposited by means previously noted.

This electron emitting material 64 is the material that will emit electrons once properly excited by incident radiation 12. Examples of this electron emitting material 64 include, but are not limited to, CdSe and PbSe. The high surface energy material 8 and electron emitting material 64 may be repeated "n" cycles to increase the electron yield of the solar energy device 54.

A second semiconducting material 66 is then supplied to the electron emitting material 64. The second semiconducting material 66 is an N-doped semiconducting material such as phosphorus doped silicon. A back grid material 68 is then supplied to the second semiconducting material 66. The back grid material 68 acts to connect the solar energy device 54 to the load 60 in conjunction with the contact grid material 58. The back grid material 68 is a metallic material that is preferably essentially reflective to the incident radiation 12. An example of the back grid material 68 is aluminum although any reflective material which is also electrically conductive and that can be bonded to the second semiconducting material 66, can connect the solar energy device 54 to a load 60 28 and that is preferably, but not required to be, reflective to incident light 12 may be used as well.

It should be understood that although several examples of the invention have been disclosed, many applications exist whereby it would be beneficial to use the present invention in the formation of nanometer scale objects 2. Other examples include, but are not limited to, electronic switching devices, optical switching devices, conjugate formation for biomedical applications, laser and LED applications, power and energy systems and solid state lighting applications. It should also be understood that the high surface energy material 8 and low surface energy material 10 selection is limited only by usefulness of these materials 8, 10 in the system or device of interest, the ability to deposit the low surface energy material 10 in a dry manner and the surface free energy of the high surface energy material 8 and low surface energy material 10.

The present invention has been described in connection with certain embodiments, configurations and relative dimensions. It is to be understood, however, that the description given herein has been given for the purpose of explaining and illustrating the invention and are not intended to limit the scope of the invention. It is clear than an almost infinite number of minor variations to the form and function of the disclosed invention could be made and also still be within the scope of the invention. Consequently, it is not intended that the invention be limited to the specific embodiments and variants of the invention disclosed. It is to be further understood that changes and modifications to the descriptions given herein will occur to those skilled in the art. Therefore, the scope of the invention should be limited only by the scope of the claims.

Claims

What is claimed is:

1. A method of forming nanometer scale quantum objects and devices therefrom, comprising the steps of: providing a high surface energy material having a first surface energy level; depositing a low surface energy material on the high surface energy material, the low surface energy material having a surface energy level lower than the surface energy level of the high surface energy material wherein the low surface energy material forms islands of low surface energy material on the high surface energy material.

2. The method of claim 1 further comprising the steps of providing a substrate and depositing the high surface energy material on the substrate.

3. The method of claim 2 wherein the step of depositing the high surface energy material on the substrate includes the step of controlling the energy of the deposition process.

4. The method of claim 2 wherein the step of providing a substrate includes the step of providing a substrate chosen from a group consisting of semiconductor wafers, foils, metal, plastic, glasses, textiles, semiconducting materials, active devices, passive devices, rigid materials, flexible materials, fibers or ceramics.

5. The method of claim 2 wherein the step of placing the high surface energy material on the substrate includes the step of placing the high surface energy material on the substrate in a continuous layer.

6. The method of claim 2 wherein the step of depositing the high surface energy material on the substrate includes the step of controlling the energy of the deposition process.

7. The method of claim 1 wherein the step of providing a high surface energy material includes the step of providing a high surface energy material chosen from a group consisting of tantalum, tungsten, molybdenum or vanadium.

8. The method of claim 1 wherein the step of depositing the low surface energy material on the high surface energy material includes the step of controlling the energy of the deposition process.

9. The method of claim 1 wherein the steps of providing a high surface energy material and depositing a low surface energy material on the high surface energy material are repeated so that layers of high surface energy material and low surface energy material are provided.

10. The method of claim 1 wherein the step of providing a high surface energy material includes the step of manipulating the surface conditions of the high surface energy material to alter the surface free energy of the high surface energy material.

11. The method of claim 10 wherein the step of manipulating the surface conditions of the high surface energy material includes the step of manipulating the surface conditions of the high surface energy material by ion assisted deposition, heating or biasing a source of the material from which the deposited high surface energy material is derived.

12. The method of claim 1 further comprising the steps of providing a substrate and depositing the high surface energy material on the substrate wherein the step of providing a high surface energy material includes the step of manipulating the surface conditions of the high surface energy material to alter the surface free energy of the high surface energy material wherein the step of manipulating the surface conditions of the high surface energy material includes the step of manipulating the surface conditions of the high surface energy material by heating or biasing the substrate.

13. The method of claim 1 wherein the step of depositing a low surface energy material on the high surface energy material includes the step of manipulating the surface conditions of the low surface energy material to alter the surface free energy of the low surface energy material.

14. The method of claim 13 wherein the step of manipulating the surface conditions of the low surface energy material includes the step of manipulating the surface conditions of the low surface energy material by ion assisted deposition, heating or biasing a source of the material from which the deposited low surface energy material is derived.

15. The method of claim 1 further comprising the steps of providing a substrate and depositing the high surface energy material on the substrate wherein the step of depositing a low surface energy material on the high surface energy material includes the step of manipulating the surface conditions of the low surface energy material to alter the surface free energy of the low surface energy material wherein the step of manipulating the surface conditions of the low surface energy material includes the step of manipulating the surface conditions of the low surface energy material by heating or biasing the substrate.

16. The method of claim 1 wherein the step of depositing a low surface energy material on the high surface energy material includes the step of providing a low surface energy material chosen from a group consisting of indium arsenide (InAs), Cadmium Selenide (CdSe), Si, CdS, GaN, AlGaN, InGaN, AlP, AlAs, AlSb, GaSb, InN, AlN, InSb, InP, MoS2, TiO2, gold sulfide and silica.

17. The method of claim 1 further comprising the steps of encasing the high surface energy material and low surface energy material in a passivation material that hermetically seals the high surface energy material and low surface energy material.

18. The method of claim 17 wherein the step of encasing the high surface energy material and low surface energy material in a passivation material includes the step of encasing the high surface energy material and low surface energy material in a passivation material chosen from a group consisting of nitrides, oxides, ionic conducting glasses, p doped semiconducting material, polycarboxy-polymers, quaternized polyamine-polymers, polysulphato-polymers, polysulpho-polymers, polyvinylphosphonic acid, electron conducting metals or dielectric layer polymers.

19. The method of claim 1 further comprising the step of exciting the low surface energy material whereby the low surface energy material produces emitted radiation.

20. The method of claim 19 wherein the step of exciting the low surface energy material includes the step of exciting the low surface energy material by impinging on the low surface energy material with solar produced light.

21. The method of claim 19 wherein the step of exciting the low surface energy material includes the step of exciting the low surface energy material by impinging on the low surface energy material with light produced by a light source.

22. The method of claim 21 wherein the light source is chosen from a group consisting of an incandescent light, florescent light, laser, LCD, LED or plasma discharge.

23. The method of claim 19 wherein the step of exciting the low surface energy material includes the step of exciting the low surface energy material by applying electrical energy of one polarity to the high surface energy material - low surface energy material boundary and electrical energy of the opposite polarity to an electron conducting material separated from the low surface energy material by a hole conducting but not electron conducting material.

24. The method of claim 23 wherein the step of applying electrical energy of one polarity to the high surface energy material - low surface energy material boundary and electrical energy of the opposite polarity to an electron conducting material separated from the low surface energy material by a hole conducting but not electron conducting material includes the step of applying electrical energy through a source of electrical power chosen from a group consisting of battery, integrated circuit, power supplies or on board power sources.

25. The method of claim 23 wherein the high surface energy material is itself connected to a first pole of a source of electrical energy.

26. The method of claim 23 further comprising the step of depositing a second electrically conducting material on the high surface energy material to connect the high surface energy material to a first pole of a source of electrical energy.

27. The method of claim 23 further comprising the steps of providing a substrate and depositing a first electrically conducting material on the substrate to electrically connect the high surface energy material - low surface energy material boundary to a second pole of a source of electrical energy.

28. The method of claim 23 further comprising the step of depositing an isolating material on the first electrically conducting material to isolate the first electrically conducting material from subsequent materials while allowing the transport of holes but not electrons and wherein the step of providing a high surface energy material having a first surface energy level includes the step of depositing the high surface energy material on the isolating material.

29. The method of claim 22 wherein the high surface energy material is itself connected to a first pole of a source of electrical energy.

30. The method of claim 29 further comprising the step of depositing a second electrically conducting material on the high surface energy material to connect the high surface energy material to a first pole of a source of electrical energy.

31. The method of claim 28 further comprising the step of depositing a second electrically conducting material to the high surface energy material to connect the high surface energy material to a first pole of a source of electrical energy.

32. The method of claim 1 wherein the devices are chosen from a group consisting of solid state light emitting devices, electrical to optical switching devices, ultra high definition displays, bioconjugate formation devices or solar energy devices.

33. The method of claim 32 wherein the solid state light emitting devices are chosen from a group consisting of general illumination devices, windows, doors, separators, decorative and architectural panels, construction materials, jewelry, sequins, surfaces, clothing, footwear, utensils, appliances, transportation, luggage, clothing accessories, business accessories, travel accessories and derivative thereof.

34. The method of claim 32 wherein the electrical to optical switching devices are chosen from a group consisting of fiber optic components, electronic circuits including logic, data transmission, video transmission, guardian circuits, control circuits and derivatives thereof.

35. The method of claim 32 wherein the ultra high definition displays are chosen from a group consisting of military displays, heads up displays, avionics displays, aerospace displays, vision implants, commercial displays including telephone, electronics devices, television, computers, and personal electronics devices, automotive displays, industrial displays, medical displays, medical instruments, invasive medical instruments, toys, games, video displays, data displays, microscope displays, analytical instrument displays, tagging displays, control displays, security displays, and derivatives thereof.

36. The method of claim 35 further comprising the step of forming pixels.

37. The method of claim 36 wherein the step of forming pixels includes the steps of: providing a substrate; forming material formed by depositing layers of material according to the steps of: depositing a high surface energy material on the substrate; depositing a low surface energy material on the high surface energy material; depositing an isolating material on the low surface energy material; depositing an electrically conducting material on the isolating material; applying a first pattern material to the material opposite the substrate wherein the first pattern material protects the materials under the first pattern material during an etching process; etching away the material not underlying the first pattern material; applying a second pattern material to the material under the first pattern material wherein the second pattern material protects the material underlying the second pattern material during a subsequent etching process; etching away the material not underlying either the first pattern material or the second pattern material; connecting the material underlying both the first pattern material and the second pattern material to source of electrical energy.

38. The method of claim 35 further comprising the step of depositing an isolating material on compiled layers of high surface energy material and low surface energy material to isolate the high surface energy material from subsequent materials wherein the isolating material allows the transport of holes but not electrons.

40. The method of claim 39 further comprising the step of depositing a second electrically conducting material on the isolating material wherein the second electrically conducting material is connected to a first pole of a source of electrical energy.

41. The method of claim 32 wherein the bioconjugate formation devices are chosen from a group consisting of bio sensing, bio imaging, markers, masking, tags, insitu probes, fluorescent labels, targeted drug delivery, photo thermally triggered devices, colorimetric assays, and derivates thereof.

42. The method of claim 41 wherein the step of providing a high surface energy material having a first surface energy level includes the step of providing a substrate having a high surface energy and wherein the step of depositing a low surface energy material on the high surface energy material includes the step of applying a doping core material having a low surface energy to the high surface energy substrate and then depositing a low surface energy shell material on the low surface energy doping core material and wherein the step of providing a substrate includes the step of providing a substrate that allows the low surface energy doping core material and low surface energy shell material to be released from the substrate.

43. The method of claim 42 wherein the step of providing a substrate that allows the low surface energy doping core material and low surface energy shell material to be released from the substrate includes the step of releasing the low surface energy core doping material and low surface energy shell material from the substrate by means chosen from a group consisting of UV exposure, solvent exposure, acid exposure, scraping, heating, etching or electrostatic release.

44. The method of claim 32 wherein the solar energy devices are chosen from a group consisting of photovoltaic energy conversion devices, solar cells and solar panels.

45. The method of claim 44 further comprising the steps of: providing a substrate; applying an anti reflective coating to the substrate; applying a contract grid material to the substrate to connect the solar energy device to a load; applying a first semiconducting material to the contact grid material; applying a high surface energy material to the first semiconducting material; applying an electron emitting material on the high surface energy material; applying a second semiconducting material to the electron emitting material; applying a back grid material to the second semiconducting material to connect the solar energy device to the load in conjunction with the contact grid material.

46. The method of claim 45 wherein the substrate is transparent to sunlight.

47. The method of claim 45 wherein the step of applying a first semiconducting material includes the step of applying a P-doped semiconducting material.

48. The method of claim 45 wherein the step of applying an electron emitting material includes the step of applying an electron emitting material chosen from a group consisting of CdSe and PbSe.

49. The method of claim 45 wherein the step of applying a second semiconducting material includes the step of applying a N-doped semiconducting material.

50. A method of forming nanometer scale quantum objects and devices therefrom, comprising the steps of: providing a substrate; depositing a high surface energy material having a first surface energy level on the substrate; depositing a low surface energy material on the high surface energy material, the low surface energy material having a surface energy level lower than the surface energy level of the high surface energy material wherein the low surface energy material forms islands of low surface energy material on the high surface energy material; encasing the high surface energy material and low surface energy material in a passivation material that hermetically seals the high surface energy material and low surface energy material.

51. The method of claim 50 wherein the steps of providing a high surface energy material and depositing a low surface energy material on the high surface energy material are repeated so that layers of high surface energy material and low surface energy material are provided.

52. The method of claim 50 further comprising the step of exciting the low surface energy material whereby the low surface energy material produces emitted radiation.

53. The method of claim 50 wherein the devices are chosen from a group consisting of solid state light emitting devices, electrical to optical switching devices, ultra high definition displays, bioconjugate formation devices or solar energy devices.

54. A device comprising: a high surface energy material having a first surface energy level; a low surface energy material deposited on the high surface energy material, the low surface energy material having a surface energy level lower than the surface energy level of the high surface energy material wherein the low surface energy material forms islands of low surface energy material on the high surface energy material.

55. The device of claim 54 wherein the devices are chosen from a group consisting of solid state light emitting devices, electrical to optical switching devices, ultra high definition displays, bioconjugate formation devices or solar energy devices.

56. The device of claim 54 further comprising a substrate and wherein the high surface energy material is deposited on the substrate.

57. The device of claim 54 wherein the high surface energy material is chosen from a group consisting of tantalum, tungsten, molybdenum or vanadium.

58. The device of claim 54 wherein the high surface energy material and low surface energy material are repeated so that layers of high surface energy material and low surface energy material are provided.

59. The device of claim 54 wherein the low surface energy material is chosen from a group consisting of indium arsenide (InAs), Cadmium Selenide (CdSe), Si, CdS, gold sulfide, silica and cadmium sulfide .

60. The device of claim 54 further comprising a passivation material layer encasing the high surface energy material and low surface energy material and hermetically sealing the high surface energy material and low surface energy material.