MXPA05009423A - Rapid generation of nanoparticles from bulk solids at room temperature - Google Patents

Abstract

A plurality of nanoparticles are provided. The nanoparticles may have a metal oxide or a semiconductor oxide surface region and a metal or semiconductor core region and/or the nanoparticles may be uniformly doped. The nanoparticles are formed by grinding a bulk material to a powder and then etching the powder in a solution to a desired nanoparticle size.

Description

RAPID GENERATION OF NANOPARTICLES FROM SOLIDS IN MASS AT AMBIENT TEMPERATURE FIELD OF THE INVENTION The present invention is directed in general to compositions of matter and more particularly to nanoparticles and methods for making them. BACKGROUND OF THE INVENTION In principle, nanoparticles of any material can be generated by completely grinding a bulk solid of the given material, by a grinding process such as ball milling, as discussed, for example, in "Large-scale synthesis of ultrafine Si nanoparticles by ball milling "(" Large scale synthesis of ultrafine Si nanoparticles by ball milling ") C. Lam, YF Zhang, Y.H. Tang, C.S. Lee, I. Bello, S.T. Lee, Journal of Crystal Growth 220 (2000) 466-470. However, as simple as it may seem, milling does not lead to uniform particle sizes due to the aggregation of the particles after they have been crushed and pulverized to sub-micron pieces. To get nanoparticles below 100 nm, it can take up to several days of grinding, making the grinding process, such as the ball milling process, unsuitable for large scale production. When the nanoparticles are produced by ball milling for a prolonged period of time, such as several days, the nanoparticles are frequently contaminated and undesirable impurities of foreign materials have been detected in such nanoparticle samples. Thus, many methods of synthesis of commercial nanoparticles use high temperature processes, including the formation of nanoparticles through the reaction of chemicals or physical disintegration of large particles by pyrolysis. However, these methods are often complex, expensive, difficult to control due to the high temperature of the process and often use chemicals environmentally - harmful and dangerous. A relatively new correlative method has been proposed for the easier manipulation and spatial organization of the nanoparticles, in which the nanoparticles are encapsulated in a shell. The covers that encapsulate the nanoparticles are composed of various organic materials such as Polyvinyl Alcohol (PVA), PMMA and PPV. In addition, semiconductor covers have also been suggested. For example, the US patents 6,225,198 and 5,505,928 incorporated herein by reference, describe a method for forming nanoparticles using an organic surfactant. The process described in the '625 patent includes providing organic compounds, which are precursors of Group II and Group VI elements, in an organic solvent. A hot mixture of organic surfactant is added to the precursor solution. The addition of the hot mixture of organic surfactant causes the precipitation of the semiconductor nanoparticles ll-VI. The surfactants cover the nanoparticles to control the size of the nanoparticles. However, this method is disadvantageous because it involves the use of a process of high temperature (above 200 ° C) and reagents and toxic surfactants. The resulting nanoparticles are covered with a layer of an organic surfactant and some of the surfactant is incorporated into the semiconductor nanoparticles. The organic surfactant negatively affects the optical and electrical properties of the nanoparticles. In another method of the prior art, the semiconductor nanoparticles I I-VI were encapsulated in a shell comprising a different semiconductor material I I-VI, as described in the U.S. patent. 6,207,229, incorporated herein by reference. However, the cover also interferes with the optical and electrical properties of the nanoparticles, decreasing the quantum efficiency of the radiation and the production yield of the nanoparticles. In addition, it has been difficult to form nanoparticles of a size - - uniform. Some researchers claimed to have formed nanoparticles in a solution that have a uniform size based on transmission electron microscopy (TEM) measurements and based on the approximation of nanoparticle size from the position of the exciton peak in the absorption spectra. of the nanoparticles. Nevertheless, the present inventor has determined that both of these methods do not lead to an exact determination of the size of nanoparticles in the solution. TEM allows the actual observation of a few precipitated nanoparticles on a substrate of a solution. However, because very few nanoparticles are observed during each test, the size of the nanoparticles varies greatly between observations of different nanoparticles from the same solution. Therefore, even if a single TEM measurement shows a few nanoparticles of a uniform size, this does not correspond to a complete nanoparticle solution of a uniform size. Using the position of the exciton peak of the absorption spectra for the approximate size of nanoparticles is problematic for a different reason. The position of the exciton peak does not show whether the individual nanoparticles in a solution agglomerate in a large cluster. Thus, the size of the individual nanoparticles estimated from the location of the exciton peak in the absorption spectra does not take into account that the individual nanoparticles have agglomerated into clusters. BRIEF SUMMARY OF THE INVENTION A preferred embodiment of the present invention provides a plurality of nanoparticles having a surface region of a metal oxide or semiconductor oxide and a core region of metal or semiconductor. Another preferred embodiment of the present invention provides a plurality of uniformly mixed nanoparticles having a - - average size between approximately 2 nm and approximately 100 nm with a standard deviation of size of less than 60 percent of the average nanoparticle size determined by the photon correlated spectroscopy (PCS) method. Another preferred embodiment of the present invention provides a method for making nanoparticles, which comprises providing a bulk material, grinding the bulk material to a powder having particles of a first size, providing the powder having particles of a first size in a solution, and provide a chemical etching liquid in the solution to chemically attack the particles of the first size to nanoparticles that have a second size smaller than the first size. Another preferred embodiment of the present invention provides a method for making nanoparticles which comprises providing semiconductor or metal nanoparticles in an oxidation solution, and oxidizing the semiconductor or metal nanoparticles in the oxidation solution to form a semiconductor oxide surface region or metal oxide on the respective semiconductor or metal nanoparticles. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a three-dimensional view of a magnetic data storage medium according to a preferred embodiment of the invention. Figure 2 is a plan view of the optical data storage medium according to another preferred embodiment of the present invention. Figure 3 is a side cross-sectional view of a bracket optical device for another preferred embodiment of the present invention. Figure 4 is a side cross-sectional view of an electroluminescent device according to another preferred embodiment of the present invention.

- Figure 5 is a side cross-sectional view of a photodetector according to another preferred embodiment of the present invention. Figures 6A and 6B are schematic illustrations of the steps in a method for making nanoparticles according to the preferred embodiments of the present invention. Figures 7-26 are PCS spectra of samples illustrating the size distribution of nanoparticles in water for silicon, silicon dioxide (SIO2) and for silicon nanoparticles covered with S02, made according to the preferred embodiments of the invention. present invention. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention has made it possible that nanoparticles can be formed by a simple process at room temperature which includes grinding a bulk material to a powder and then chemically attacking the powder in a solution to achieve a desired nanoparticle size. . Thus, the process generates the nanoparticles from a bulk solid at temperatures below 100 C, such as below 50 C, preferably at room temperature. Due to the simplicity, uniformity and speed of this process, nanoparticles of any material can be manufactured in large quantities with a very approximate size distribution compared to any other existing method, such as ball milling alone or with pyrolysis. For example, metal, semiconductor and metal oxide or semiconductor oxide nanoparticles, such as nanoparticles of silicon, silica, alumina and aluminum, can be synthesized using this method. The term "nanoparticles" includes particles having an average size between about 2 and about 100 nm, preferably particles having an average size between about 2 and about 50 nm. More preferably, the nanoparticles comprise quantum dots having an average size between about 2 and about 10 nm. Preferably, the - - first standard deviation of the size distribution is 60% or less, preferably 40% or less, more preferably 10 to 25% of the average particle size. A method for making nanoparticles according to the first preferred embodiment includes providing a bulk material, such as a piece of mass material. The method further includes grinding the bulk material to a powder having particles of a first average size, such as nanoparticles and / or microparticles. The powder having particles of a first size is provided to a solution. A chemical etch liquid is also provided in the solution to chemically attack the first size particles to nanoparticles having a second desired size smaller than the first size. The bulk material can have any suitable shape for grinding and can comprise any desired material that can form nanoparticles. For example, the bulk material can be a semiconducting mass material, such as a Group VI semiconductor material (Si, Ge, SiC, SiGe), ll-VI (CdS, ZnS, CdSe, ZnSe, ZnTe, CdTe), IV-VI (PbS, PbSe, PbTe) or an lll-V (GaAs, GaP, GaN, InP, InAs). The tertiary and quaternary semiconductor nanoparticles, such as for example CdZnS, CdZnSe, CdZnTe, CdZnTeSe, CdZnSSe, GaAlAs, GaAlP, GaAlN, GalnN, GaAlAsP and GaAlInN, can also be used. Preferably, the bulk material comprises a uniformly mixed semiconducting mass material, such as a single uniformly mixed crystal, pellet, monocrystal or polycrystalline or amorphous semiconductor layer, formed on a substrate. More preferably, the bulk material comprises at least a portion of a silicon wafer uniformly mixed with suitable Group III or Group V adulterants such as B, P, As and / or Sb. Alternatively, the bulk material comprises a material in ceramic mass, such as ceramic glass. For example, the ceramic material - - it may comprise silica, alumina, titania, zirconia, zirconia stabilized with tria, tria, ceria, spinel (for example, MgO * AI203) and tantalum pentoxide, as well as other suitable ceramics having a more complex structure such as phosphors which emit radiation (for example, YAG: Ce (YaAlsO-i ^ Ce) and several of halophosphate, phosphate, silicate, aluminate, borate and tungstate phosphors) and scintillators (for example, LSO, BGO, YSO, etc.). If desired, other materials, such as quartz or glass, can also be used. Alternatively, the bulk material comprises a metal, such as a pure metal or an alloy of metals, having some suitable shape, such as a rod, rod, etc. Any suitable material can be used, such as Al, Fe, Cu, Ni, Au, Ag, Pt, Pd, Ti, V, Ta, W, Mn, Zn, Mo, Ru, Pb, Zr, etc. Preferably, the metal comprises an alloy of metals (eg mixed metals) having any suitable alloy composition, such as steel, Inconel, Permendur and other suitable alloys. The bulk material can be reduced to powder by any suitable milling method. For example, the bulk material can be milled to a powder by grinding, such as by ball milling. However, in a first preferred aspect of the first embodiment, the grinding step comprises placing a piece of the material in mass on an abrasive film and moving the piece and the abrasive film in relation to each other to grind the bulk material to a powder . For example, as shown in Figure 6A, a solid piece or piece of bulk material 1 moves on a fixed abrasive film 3 with spherical or sharp abrasive tips. The size of the mechanically removed particles is of the order of the dimensions of the tip. Unlike the ball milling process, this process generates particles of more uniform size, such as microparticles or nanoparticles. The particles are preferably suspended in a liquid during the milling process, such as water or glycerol. Subsequently, their sizes are adjusted by a combination of chemical etching and optionally centrifugation, filtering through a porous medium, sonification and surface coating, as will be described in more detail below. The chemical etch liquid can be provided in the solution before or after providing the powder to the solution. For example, the solution may comprise aqueous HCl, HF, NaOH or KOH wherein the solute is the etchant liquid and the water is the solvent. Alternatively, the etchant liquid itself may comprise a first solution that is added to a second solution before or after adding the powder to the second solution. Thus, nanoparticles or nanocrystals having sizes in the range of 2 - 100 nm and with size distribution in the range of 10-25% of average size can be made using the method of the first preferred embodiment. Preferred examples for making nanoparticles of different materials are briefly described below. The polycrystalline pieces of Al, Si, silica and alumina were taken and crushed on a fixed abrasive film of diamond and silicon carbide of 0.1 to 1 miera of size. The abrasive film was rotated and / or the pieces moved on the abrasive film. During the milling process, the abrasive film was washed with water and the abradiated "primary" nanoparticles were collected in a container. The primary nanoparticles are then chemically etched into a solution using suitable etchant reagents such as KOH, HF, NaOH, HCI and other acids and bases (a suitable reactant reagent liquid is selected for each particular material). Optionally, the surface cover was provided by standard anionic or cationic surfactants. Thus, ground nanoparticle powder with a large average size and a non-uniform size distribution can first be provided in a solution. After, the reaction reactive liquid is added to the solution and the solution is stirred, such as by means of a magnetic stirrer. The reactive attack liquid reduces the size of the nanoparticles to the desired size by chemically attacking the nanoparticles. Thus, the attack reagent "adjusts" the nanoparticles to the desired size. The general reaction chemistries for the chemical attack stage of the exemplary PbS and CdS nanoparticles are shown below: PbS + H2O + 2HCI? PbCI2 + H2S + H2O (1) CdS + H20 + 2HCI? CdCI2 + H2S + H20 (2) The model representing the size adjustment of the PbS nanoparticles is shown in Figure 6B. First, PbS nanoparticles with a large size are provided in a solution in water. Then, HCl is added to the solution (Table 61 in Figure 6B). The HCI reacts with the PbS nanoparticles and forms PbCI2 and H2S (Table 63 in Figure 6B). PbS nanoparticles chemically attacked with the smallest and uniform size remain in the water. PbCl2 remains dissolved in water while the volatile H2S gas escapes from the solution (Table 65 in Figure 6B). The excess passivation element in the solution, such as sulfur, then re-passivates the surface of the chemically attacked nanoparticles. By selecting an appropriate type and amount of etching medium, large nanoparticles can be chemically attacked automatically for a uniform smaller size. If the concentration of acid in the solution exceeds the desired amount then the nanoparticles are completely dissolved. Preferably, the etchant liquid is diluted in water to form a first solution and then the first solution is added to a second solution in small amounts. For example, the size adjustment of the PbS nanoparticles is made by adding a solution of the HCl: H 2 O dilution (1: 50 percent by volume, where 1 ml of HCl is dissolved in 50 ml of H 2 O) to the water containing the nanoparticles. This solution of HCI: H2O is added to the water containing the nanoparticles in small amounts, such as in quantities of 2 ml, until the size of the nanoparticle is adjusted.

- To reduce the size distribution, preferably one or more stages of purification or separation of particles are carried out. One such particle separation step comprises centrifuging a container containing the solution after the etching step (Le. Centrifuging the solution containing the formed nanoparticles). Distilled water is added to the sample and the nanoparticles are agitated again in solution in an ultrasonic vibrator. If desired, the centrifugation and washing process can be repeated a plurality of times. The above solution is then filtered through mesh or filters after the centrifugation and washing steps. The mesh or filter can be made of randomly oriented stacks of cellulose, spherical columns of dielectric materials, polymers, nanoporous medium (such as alumina or graphite). An alternative method for making the nanoparticles with a specific size is to decant the solution by storing it for several hours. A first set of heavy or large nanoparticles or nanoagrupamientos settle in the bottom of the container. The second set of smaller nanoparticles remains located in the upper portion of the solution that separates from the first set of nanoparticles and is withdrawn into a new container from the top of the solution. This process can be repeated several times to separate the nanoparticles with different sizes. During each successive step, the original reagent solution is diluted with a liquid medium that does not dissolve the nanoparticles, such as water. The settling step can be used in place of or in addition to the centrifugation and filtration steps. After manufacture storage and / or transport, the nanoparticles can be suspended in fluid, such as a solution, suspension or mixture. Suitable solutions can be water as well as organic solvents such as acetone, methanol, toluene, alcohol and polymers such as polyvinyl alcohol. Alternatively, the nanoparticles are - locate or deposit on a solid substrate or in a solid matrix. Suitable solid matrices can be glass, ceramic, cloth, leather, plastic, rubber, semiconductor or metal. The fluid or solid comprises an article of manufacture that is suitable for a certain use. The method of the first preferred embodiment is advantageous because it provides the manufacture of uniformly mixed nanoparticles (eg, nanocrystals). The incorporation of adulterants (the adulterants are called "alloying elements" in metals) is very difficult and unreliable when the nanoparticles are manufactured by the high temperature chemical synthesis of the prior art due to the fact that the number of surface atoms and volume are almost similar. In the method of the first preferred embodiment, the adulterants are already incorporated and chemically bound to the base grid in the bulk material. Consequently, the adulterants are uniformly distributed and present in almost all nanoparticles. This is due to the fact that the original bulk material can be developed or manufactured at high temperature and in a very high quality and ultra-pure form under conditions of equilibrium development. The rapid fragmentation of the mass to nanoparticles during the milling stage ensures high quality for the final nanoparticles. Thus, rapid large-scale production of high-quality nanoparticles is possible. In addition, the initial size distribution of the nanoparticles is significantly closer compared to the nanoparticles manufactured by a single ball mill process. The method of the first preferred embodiment is universal and can be used to create nanoparticles of any material. The nanoparticles made by the method of the first preferred embodiment comprise nanoparticles having an average size between about 2 nm and about 100 nm with a standard deviation of size of less than 60% of the average size of the nanoparticles determined by the photon correlated spectroscopy (PCS) method. The PCS method has been used to determine the size - - of the nanoparticles in a suspension. The size of the nanoparticles can also be determined using Secondary Electron Microscopy (SEM) (Secondary Electron Microscopy), Transmission Electron Microscopy (TEM) (Transmission Electron Microscopy) or Atomic Forcé Microscopy (AFM) (Atomic Force Microscopy). Preferably, the nanoparticles have an average size between about 2 nm and about 10 nm with a size standard deviation of between about 10 and about 25% of the average nanoparticle size determined by the photon correlated spectroscopy (PCS) method. More preferably, the nanoparticles are uniformly mixed nanoparticles. In a preferred aspect of the first embodiment, the term "uniformly blended nanoparticles" means that each uniformly blended nanoparticle has a concentration of adulterant varying by less than 5%, preferably less than 1% throughout its volume. In another preferred aspect of the first embodiment, the term "uniformly mixed nanoparticles" means that the nanoparticles have an average concentration of adulterant that varies by less than 5%, preferably less than 1% between the nanoparticles. In other words, each nanoparticle of the plurality of nanoparticles has an average concentration of adulterant that is within 5%, preferably within 1% of the other nanoparticles within the plurality of nanoparticles, such as a plurality of randomly sampled nanoparticles produced from the same batch of nanoparticles. The term "adulterant" includes adulterant ions in semiconducting nanoparticles such as B, P, As or Sb in Si nanoparticles, dopant ion in metal oxide ceramic phosphorus and scintillator nanoparticles, such as Ce3 + ions in YAG nanoparticles , and alloying elements in metal alloys, such as C in Fe nanoparticles. In a preferred aspect of the first embodiment, the nanoparticles are capable of suspending in water without substantial agglomeration and substantial precipitation on the surfaces of the containers for at least 30 days , preferably at least 90 days. This means that at least 70%, preferably 95%, more preferably more than 99% of the nanoparticles are suspended in water without agglomeration and precipitation on the bottom and walls of the container. It should be noted that the nanoparticles can also be suspended in liquids other than water without substantial agglomeration and substantial precipitation on the surfaces of the container for at least 30 days, preferably for at least 90 days. Nanoparticles can be used in various fields of technology, such as nanotechnology, semiconductors, electronics, biotechnology, coatings, agriculture and optoelectronics, as will be described in more detail below. In a second preferred embodiment of the present invention, the surface of semiconductor or metal nanoparticles is modified to form a semiconductor oxide or metal oxide surface region. For example, a surface of silicon nanoparticles can be modified to a surface of silicon dioxide, or a surface of aluminum nanoparticles can be modified to an aluminum oxide surface, by suspending the nanoparticles in an oxidizing solution. A method for making nanoparticles according to the second preferred embodiment comprises providing semiconductor or metal nanoparticles in an oxidant solution and then oxidizing the semiconductor or metal nanoparticles in the oxidant solution to form a semiconductor or oxide oxide surface region. metallic on the respective semiconductor or metal nanoparticles. Of course the surface of the nanoparticles can also be modified to a nitride, such as a semiconductor nitride (such as silicon nitride) or metal nitride (such as aluminum nitride) by using a nitrurant solution instead of an oxidizing solution. Preferably, a bulk metal or semiconductor material is - grind first as described above to form the semiconductor or metal nanoparticles before providing semiconducting or metal nanoparticles in an oxidizing (or nitriding) solution. Any suitable oxidizing solution can be used. For example, for silicon nanoparticles, a dilute, aqueous NaOH or KOH solution can be used to oxidize the nanoparticles. In a preferred aspect of the second embodiment, the same solution is used to attack with acid and oxidize the nanoparticles. For example, an aqueous acidic solution having a pH less than 7 contains both HF and NaOH in suitable amounts. As the ground semiconductor or metal nanoparticles are provided in the solution, the HF chemically attacks the nanoparticles to a desired size, until the reactive fluorine ions are depleted. Next, the NaOH in the solution oxidizes the surface of the nanoparticles. In another preferred aspect of the second embodiment, different solutions are used to chemically attack and oxidize (or nitride) the nanoparticles. For example, milled nanoparticles may first be introduced into a first solution containing a chemical etchant liquid such as HF, with a pH below 7 to chemically attack the nanoparticles to a desired size. The nanoparticles are then removed from the first solution and placed in a second oxidant solution, such as a solution containing NaOH or KOH having a pH above 7 to oxidize the nanoparticles. Alternatively, the first solution is converted to the second solution by adding the oxidizing agent, such as NaOH or KOH, in the first solution after the completion of the etching step. If this is desired to nitride the nanoparticles, then a nitrurant solution such as aqueous ammonia solution may be used instead. The nanoparticles of the second preferred embodiment have a metal oxide or semiconductor oxide surface region and a metal or semiconductor core region. The nanoparticles also contain a transition region located between the surface region and the core region. The ratio of oxygen to metal or semiconductor in the transition region is the maximum adjacent to the surface region and gradually decreases toward the core region. Preferably the core region does not contain oxygen atoms or contains a trace amount of oxygen atoms, such as less than 1 atomic% oxygen. Thus, the semiconductor nanoparticles comprise a semiconductor core region of Si, Ge, SiGe, ll-VI, IV-VI or III-V, and an oxide surface region of Si02, Ge02, ll-VI, IV-VI or III-V. For example, Si nanoparticles have a Si core region, a SiO2 surface region and a silicon rich SiO2-x transition region, where x varies from 2 adjacent to the surface region to approximately 0 adjacent to the core region. Preferably the Si core regions of the nanoparticles are uniformly mixed with a suitable Group III or Group V adulterant. The metal nanoparticles comprise a metal core region and a metal oxide surface region. For example, Al nanoparticles comprise an Al core region, a surface region of AI2 3 3, and an aluminum rich AIOx transition region, where x varies from 3/2 adjacent to the surface region to approximately 0 adjacent to the core region. As in the first embodiment, the preferred average size of the nanoparticles is from 2 to 100 nm with a size distribution of 10 to 25%. The nanoparticles preferably have an average size between about 2 nm and about 100 nm with a size standard deviation of less than 60% of the average nanoparticle size measured by the photon correlated spectroscopy (PCS) method. The following from the first to the twenty-sixth preferred embodiments provide preferred articles of manufacture incorporating - -the nanoparticles made by the methods of the first and second processing modes. It should be noted that although these articles of manufacture preferably contain the nanoparticles of the first and second embodiments, as described above, they may also contain metal or insulating nanoparticles (such as ceramics) that are made by any other method including by the methods of the art previous. In the first four preferred embodiments, the nanoparticles are provided in a fluid. In a first preferred embodiment, the nanoparticles are placed in a polishing mixture. The nanoparticles are dispersed in the fluid of the polishing mixture. Since nanoparticles have a very high surface hardness due to their small size, the nanoparticles function as an abrasive medium in the fluid of the mixture. If desired, another abrasive means may be added in addition to the nanoparticles to the mixture. The polishing mix can be used to polish any industrial item, such as metals or ceramics. Preferably, the mixture is adapted for use in a chemical-mechanical polishing apparatus used to polish pellets and semiconductor devices. In this case, in addition to the nanoparticles, the mixture also contains a chemical that chemically removes a portion of the chips and semiconductor devices. In a second preferred embodiment, the nanoparticles are placed in a paint. The nanoparticles are dispersed in the liquid base of the paint. Since the nanoparticles have a uniform size distribution, they provide a substantially uniform color to the paint. In a preferred aspect of the second embodiment, the liquid base of the paint is selected so that it evaporates after it is coated on a surface, such as a wall, ceiling or floor. After the liquid base evaporates, a layer of nanoparticles is left on the surface so that the nanoparticles provide a color to the surface. The nanoparticles adhere very strongly to the surface due to their small size. The nanoparticles are almost impossible to remove by physical means, such as brushing, spatulas of painter or scrubber since the size of the nanoparticles is smaller than the grooves present on the surfaces of the brushes, spatulas of painter or scrubbers. Thus, a chemical method, such as acid etching, is required to remove the nanoparticles from the surface. Therefore, the paint containing nanoparticles is specially adapted to function as a protective paint, such as a primer that inhibits oxidation (which is provided under a conventional paint layer) or a topcoat paint (which is provided over a conventional paint layer). Thus, paint containing nanoparticles is specially adapted to cover external structures, such as bridges, fences and buildings, as it adheres much better to surfaces than conventional paints, primer paints and top coatings. In a third preferred embodiment, the nanoparticles are placed on an ink. The nanoparticles are dispersed in a liquid ink. As described above, the nanoparticles can provide a substantially uniform color to a liquid. Thus, by placing the nanoparticles in an ink, once the dried ink and the liquid base evaporate, an image of a nanoparticle layer is formed. This image will have a very high adhesion to the surface on which it is painted. The ink may comprise a computer printer ink (Le. Inkjet printer, efe), printing press ink, pen ink or tattoo ink. In a fourth preferred embodiment, the nanoparticles are placed in a cleaning composition. The nanoparticles are dispersed in the cleaning fluid. Since the nanoparticles have a high surface hardness, they add a significant purifying powder to the cleaning fluid. The cleaning fluid may comprise any industrial cleaning fluid, such as a cleaning fluid / surface scrubber or a pipe cleaning fluid. In the first four preferred modalities, the nanoparticles - - they are provided in a fluid. In the following preferred embodiments, the nanoparticles are provided on a surface of a solid material. In the fifth preferred embodiment, the nanoparticles comprise a hard or wear resistant coating located on at least a portion of a device. The device can be any device in which hard or wear resistant coating is desired. For example, the device can be a tool (such as a screwdriver, saw blade), a drill bit, turbine blade, a gear or a cutting apparatus. Since nanoparticles have a high surface hardness and very strong adhesion to a substrate, a layer of nanoparticles provides a coating of ideal hardness or wear resistance for a device. The coating can be formed by providing a fluid containing the nanoparticles and then evaporating or otherwise removing the fluid to leave a layer of nanoparticles on the surface of the device. In the sixth preferred embodiment, the nanoparticles comprise a moisture barrier layer located on at least one surface of an article of manufacture. The moisture barrier layer has little or no pore for water or moisture to run off through the layer because the layer comprises a plurality of small sized nanoparticles that contact each other. The size of the individual nanoparticles is much smaller than the size of a drop of moisture. Thus, a continuous layer of nanoparticles will resist the penetration of moisture. The article of manufacture that contains the nanoparticles can be clothing (lecks, pants, etc. made of cloth or leather) or footwear (made of leather, cloth, rubber or artificial leather). Alternatively, the article of manufacture could comprise a structure, such as a bridge, building, awning, sculpture, etc. For example, since the nanoparticle layer has a greater adhesion to the structure than the conventional moisture barrier paint, using the nanoparticle moisture barrier would reduce or eliminate the requirement that the moisture barrier be reapplied each few years - (as is currently done with bridges). The moisture barrier layer can be deposited by providing a fluid containing the nanoparticles and then evaporating or removing the fluid in order to leave a layer of nanoparticles on the surface of the article. Preferably, the layer is formed on an external surface of the article. If desired, the nanoparticle material could be selected to absorb sunlight and generate heat when exposed to sunlight (Le. CdTe nanoparticles), Alternatively, the material can be selected to trap heat emitted by a human body. . In a seventh preferred embodiment, the nanoparticles are provided in a compound of ultra low porosity material. Preferably, such material has a porosity below 10 volume percent, more preferably below 5 volume percent. The composite material comprises a solid matrix material and nanoparticles incorporated in the matrix. The composite material can be formed by mixing a powder of matrix material and nanoparticle powder together and then compressing the mixed powder to form a composite material. Since the nanoparticles have a small size, they occupy the pores in the matrix material to form an ultra-low porosity composite material. The matrix material may comprise ceramic, glass, metal, plastic, or semiconductor materials. The ultra low porosity material can be used as a sealant such as a tire seal. Alternatively, the composite material can be used as a load in industrial and medical applications. In an eighth preferred embodiment, the nanoparticles are provided in a filter. A nanoparticle powder can be compressed to form the filter. Alternatively, the nanoparticles can be added to a solid matrix material to form the filter. Since the nanoparticles have a small size, the compressed nanoparticles or nanoparticles in a matrix have a low porosity. Thus, the nanoparticle filter has a very fine "mesh" and is capable of filtering very small particles. The porosity of the filter is greater than the porosity of the ultra low porosity material of the previous embodiment. Preferably, the filter is used to filter a liquid containing very small solid particles. The liquid containing the particles is emptied through the filter, which traps the particles above a predetermined size. In a ninth preferred embodiment, the nanoparticles are provided in a composite of high strength structural material. Since the nanoparticles have a high surface hardness and low porosity, the nanoparticles can be incorporated into a composite structural material that has a solid matrix and nanoparticles dispersed in the matrix. The matrix material may comprise ceramic, glass, metal or plastic. The structural material can be used in buildings such as columns and support walls and in bridges as roads and as supporting columns. The structural material can also be used to form parts of machinery and vehicles, such as cars and trucks. In a tenth preferred embodiment, the nanoparticles are provided in an environmental detector. The environmental detector includes a radiation source, such as a lamp or laser and a matrix material containing the nanoparticles. The matrix material may comprise liquid, gas or solid material. The detector is exposed to an external medium that affects the light emission properties of the nanoparticles. For example, the detector may comprise a contamination detector that is exposed to the atmosphere. The amount of pollution in the atmosphere affects the microenvironment of the nanoparticles, which in turn affects their radiation emission characteristics. The nanoparticles are irradiated with radiation, such as visible light or UV or IR radiation from the radiation source. The radiation emitted and / or absorbed by the nanoparticles is detected by a detector. A computer then determines the amount of pollution present in the atmosphere based on the radiation detected using a standard algorithm.

- The detector can also be used to detect gas components and compositions other than the amount of pollution in the atmosphere. Nanoparticles can also be used in lighting applications. From the eleventh to the thirteenth modality describe the use of nanoparticles in lighting applications. In the eleventh preferred embodiment, the nanoparticles are used as a light emitting medium in a solid state light emitting device, such as a laser or light emitting diode. In these applications, a current or voltage is supplied to the nanoparticles from a current or voltage source. The current or voltage causes the nanoparticles to emit light, UV or IR radiation, depending on the material and size of the nanoparticles. In the twelfth preferred embodiment, the nanoparticles are used to provide the support for the organic light-emitting material in an organic light-emitting diode. An organic light-emitting diode contains an organic light-emitting material between two electrodes. The organic light-emitting material emits light when current or voltage is applied between the electrodes. The organic material that emits light may be a polymeric material or small dye molecules. Both of these organic materials have poor structural characteristics and impact resistance, which decreases the robustness of organic light-emitting diodes. However, these organic light emitting materials can be incorporated into a nanoparticle matrix that provides the desired structural characteristics and impact resistance. Since the nanoparticles have the same or smaller size as the dye or polymer molecules, the nanoparticles do not interfere with the light emitting characteristics of the diode. In the thirteenth preferred embodiment, the nanoparticles are used in a fluorescent lamp instead of a phosphorus. In a conventional fluorescent lamp, a phosphor is coated on an inner surface of a lamp cover. Phosphorus absorbs UV radiation emitted by - - a radiation source, such as mercury gas located on the lamp cover, and emitting visible light. Since certain ceramic nanoparticles have the ability to absorb the UV radiation emitted by the radiation source and emit visible light, these nanoparticles can be located on at least one surface of the lamp cover. Preferably the nanoparticle layer coated on the lamp cover contains nanoparticles that emit light of different color, so that the combined light emission of the nanoparticles appears as white light to a human observer. For example, the different color light emitter can be obtained by mixing nanoparticles having a different size and / or nanoparticles of different materials. Nanoparticles can also be used in magnetic data storage applications. The fourteenth and fifteenth preferred embodiments describe the use of nanoparticles in magnetic data storage applications. In the fourteen preferred embodiment, the nanoparticles are used in a magnetic data storage device. The device includes a magnetic field source, such as a magnet, a data storage medium, comprising the nanoparticles, a photodetector. A light source is used to illuminate the nanoparticles. The magnetic field source selectively applies a magnetic field source located to a portion of the data storage medium. The application of the magnetic field causes the nanoparticles exposed to the field to charge their characteristics of light emission or radiation or extinguish the emission of light or radiation all at once. The photodetector detects the radiation emitted from the nanoparticles in response to the application of a magnetic field by the magnetic field source. In a fifteenth preferred embodiment, the nanoparticles are used in a magnetic storage medium containing a magnetic material. The magnetic material can be any magnetic material that - - can store data by aligning the directions of the turns in the material. Such magnetic materials include, for example, cobalt alloys, such as CoPt, CoCr, CoPtCr, CoPtCrB, CoCrTa and iron alloys, such as FePt and FePd. In a preferred aspect of the fifteenth embodiment, the nanoparticles 11 are randomly mixed through a layer of a magnetic material 13 formed on a substrate 15, as shown in Figure 1. The substrate 15 can be glass, quartz , plastic, semiconductor or ceramic. The randomly dispersed nanoparticles are located within the magnetic domains in the magnetic material. The domains are separated by the walls of the domains. A few domain walls are shown by lines 17 in approaching area "A" in Figure 1. Dispersed nanoparticles form barrier layers 19 within the domains. The barrier layers form domain walls in the magnetic material. Therefore, the addition of the nanoparticles has the effect of subdividing the domains in the magnetic material into a plurality of "subdomains" each of which is capable of storing one bit of data (shown as spin arrows in Figure 1). ). Thus, the addition of the nanoparticles increases the data storage density of the magnetic material by decreasing the size of the domain in the magnetic material. In a second preferred aspect of the fifteenth embodiment, the magnetic storage medium comprises a substrate containing the nanoparticles mixed with atoms of the magnetic material. Each of the nanoparticles is adapted to store one bit of data. Thus, the small nanoparticles of the magnetic material are encapsulated in the nanoparticles. In this case the size of a data store bit is only as large as the nanoparticle. The magnetic nanoparticles can be mixed into the nanoparticles using any of the known mixing techniques, such as solid, liquid or gas phase diffusion, ion implantation or co-deposition. Alternatively, the magnetic nanoparticles can be encapsulated within the nanoparticles by a - treatment of plasma arc discharge of nanoparticles in contact with magnetic nanoparticles. Similar methods have previously been described for encapsulating magnetic particles in carbon and anti-diffuser tube covers (see U.S. Patents 5,549,973, 5,456,986 and 5,547,748, incorporated herein by reference). In the sixteenth preferred embodiment, the nanoparticles are used in an optical data storage medium, as shown in Figure 2. The nanoparticle clusters 21 are arranged in predetermined patterns on a substrate 25, so that the first areas 27 of the substrates 25 contain the nanoparticles 21 while the second areas 29 of the substrate 25 do not contain the nanoparticles 21. The nanoparticles 21 in a solution can be selectively dispersed from an inkjet printer or other micro-provider to the areas 27 on the substrate . After the solvent evaporates, a nanoparticle cluster remains in the areas 27. The substrate 25 can be a glass, quartz, plastic, semiconductor or ceramic substrate. Preferably, the substrate 25 is shaped like a disk, similar to a CD. The data of the storage medium is read similar to a CD, when scanning the medium with a laser or other source of radiation. The nanoparticles 21 reflect and / or emit light or radiation differently from the exposed substrate areas 29. Therefore, when the substrate is scanned by a laser, a quantity and / or wavelength of radiation different from the areas 27 that of the areas 29 by means of a photodetector. Thus, the areas 27 correspond to a data value "1", while the areas 29 correspond to a data value "0", or vice versa (Le., Each cluster of nanoparticles 21 is a data bit). Therefore, the nanoparticles 21 function similar to the attached memories in a conventional CD or as a material of a first phase in a phase change optical disc. The areas 27 can be arranged in tracks or sectors similar to a CD for ease of reading data. The optical data storage medium described above - - it can be used in combination with an optical system of the seventeenth preferred embodiment. The optical system 30 includes at least one microménsula 35 and the light-emitting nanoparticles 31 located on a tip of the at least one microménsula, as shown in Figure 3. The microménsula 35 can be a microménsula of atomic force microscope (AFM) or a microménsula similar to that which is not part of an AFM. For example, microménsula 35 can be conductive or contain conductors or conductive cables that provide current or voltage to the nanoparticles to make them emit light or radiation. The base 33 of the microménsula is connected to a source of voltage or current. The microménsula 35 can be explored on the substrate 25 containing the nanoparticles 21 of the previous embodiment. The nanoparticles emitting light 31 on the bracket irradiate the substrate 25, and the emitted and / or reflected light is detected by a photodetector and analyzed by a computer to read the data. Of course, the optical system 30 can be used to read data from a conventional CD or phase change optical disc instead of the medium of the previous embodiment. In addition, one or more micromills 35 can be incorporated into an AFM to study the surfaces of materials. In this case, the AFM can be used to study the interaction of the light or radiation emitted by the nanoparticles 31 and the surface being studied. From the eighteenth to the twenty-first preferred embodiments, the nanoparticles are used in an optoelectronic component. In the eighteenth preferred embodiment, the light-emitting nanoparticles are used in an optical switch. In the commutator, the light-emitting nanoparticles are arranged in a substrate and connected to a source of voltage or current that provides the voltage or current for the emission of light (or radiation). A magnetic field source, such as a magnet, is provided adjacent to the nanoparticles. When the magnet is turned on, it extinguishes the radiation emitted by the nanoparticles. In the nineteenth preferred embodiment, the nanoparticles are - - used in an electroluminescent device, such as the electroluminescent device illustrated in the US patent. 5,537,000, incorporated herein by reference. The electroluminescent device 40 includes a substrate 45, a free positive charge injection layer 46, a free positive charge transport layer 47, an electron transport layer 41 and an electron injection layer 48 as illustrated in FIG. Figure 4. A voltage is applied between layers 46 and 48. The voltage generates positive free charges in layer 46 and electrons in layer 48. The free positive charges and electrons travel through layers 47 and 41 and recombine to emit light. Depending on the applied voltage, recombination occurs either in layer 41 to emit red light or in layer 47 to emit green light. The electron transport layer 41 comprises a layer of nanoparticles, such as the nanoparticles I I-VI. The free positive charge injection layer 46 comprises a conductive electrode, such as indium tin oxide. The free positive charge transport layer 47 comprises an organic polymeric material, such as poly-p (paraffelino). The electron injection layer 48 is a metal or semiconductor electrode with many impurities, such as an electrode of Mg, Ca, Sr or Ba. In a twentieth preferred embodiment of the present invention, the nanoparticles are used in a photodetector 50, such as a photodetector described in the US patent. 6,239,449, incorporated herein by reference. As shown in Figure 5, the photodetector is formed on a substrate 55. A first contact layer with many impurities 52 is formed on the substrate. A first barrier layer 53 is formed on the contact layer 52. One or more layers of nanoparticles 51 are formed on the barrier layer 53. A second barrier layer 54 is formed on the nanoparticle layer (s) 51. A second contact layer with many impurities 56 is formed on the second barrier layer 54. The electrodes 57 and 58 are formed in contact with the contact layers 52, 56. The barrier layers 53, 54 are mixed to provide cargo vehicles and for - conductivity. The barrier layers 53, 54 have a ter band gap than the nanoparticles 51. The incident light or radiation excites the charging vehicles (Le electrons or positive free charges) in the nanoparticles for a ter energy than the energy of the spaces band of the barrier layers 53, 54. This causes a current flowing through the photodetector 50 from the emitting electrode to a collector electrode in response to light or incident radiation with the help of an external voltage applied between the electrodes. In a twenty-first preferred embodiment, the nanoparticles are used in a transmission grid. The nanoparticles are arranged on a transparent substrate in a grid form. Since the nanoparticles have a very small size, the grid can be formed with a period smaller than the wavelength of light or radiation that will be transmitted through the grid. Such reticles can be used in wave plates, polarizers or phase modulators. Grids can be formed by designing the nanoparticles on the substrate using sub-micron optics, X-ray or electron beam lithography or by placing individual nanoparticles on the substrate using an AFM or a scanning electron microscope of tunnel-quantum effect. mechanic. In a twenty-second preferred embodiment, the nanoparticles are used in an optical filter. The optical filter may comprise a transparent matrix of glass, plastic or ceramic with interdispersed nanoparticles. Since nanoparticles absorb radiation that has a wavelength longer than the cut-off wavelength based on the material and size of the nanoparticles, the filter can be designed to filter a range of particles of wavelengths of light or radiation UV that depend on the material and size of the nanoparticles. In addition, the nanoparticles can be used to provide a color to a particular solid material, such as stained or colored glass. In the twenty-third preferred embodiment, nanoparticles are used in electronic devices, such as transistors, resistors, diodes and other nanodevices. For example, nanoparticles can be used in a single electron transistor, as described in the U.S. Patent. 6,057,556, incorporated herein by reference. The nanoparticles are located on a substrate between a source and a drain electrode. The nanoparticles comprise a single electron transistor channel. A plurality of nanoscale gate electrodes are provided on or adjacent to the nanoparticles. The device operates on the principle of the correlated single electronic quantum mechanical mechanical tunnel effect controlled between the source and the drain electrodes through the potential barriers between the nanoparticles. A single electron gate circuit can be constructed using this device, wherein the Logical "1" and "0" are identified by the presence or absence of an electron. An example of a nanodevice array is an integrated circuit architecture called a cellular automata. With this architecture, the processor portion of the IC is composed of multiple cells. Each of the cells contains a relatively small number of devices, which communicate only with their nearest neighbor cells. This architectural procedure eliminates the need for large intercell connections, which ultimately places an upper limit on the faster processing capabilities of an electronic integrated circuit. Each cell would consist of approximately five nanoparticles or quantum dots. In the twenty-fourth preferred embodiment, the nanoparticles are used as a code or a label. For example, nanoparticles can be formed into a miniature bar code by AFM, STM or lithography. This bar code can be formed on small items, such as integrated circuits and can be read by a miniature bar code reader. Of course the code can have different symbols to the bars. In another example, the nanoparticles can be used as a label (Le., Where the nanoparticles are not formed in a particular form). Since a small amount of the nanoparticles is invisible to the human eye, the nanoparticle code or label can be added to an article that must be authenticated, such as currency, a letter of credit, an identification card or a valuable object. To authenticate the article, the presence of the nanoparticles on or in the article is detected by a microscope or by an optical detector. In addition, nanoparticles of a certain size that emit a particular wavelength of light can be used to distinguish different objects. Combinations of the different sizes of nanoparticles that emit a combination of different wavelengths can be used to emit an optical code for more accurate information of the article. In the twenty-fifth preferred embodiment, the nanoparticles are used as detector probes. For example, a detector probe can be formed by binding nanoparticles to affinity molecules using binding agents, as described in US Pat. 6,207,392, 6,114,038 and 5,990,479, incorporated herein by reference. The affinity molecules are capable of selectively binding to a predetermined biological or different substance. In response to an energy application, the nanoparticles emit light or radiation which is detected by a detector. In this way, the presence, location and / or properties of the predetermined substance linked to the affinity molecule can be determined. Binding agents can be polymerizable materials, such as N- (3-aminopropyl) 3-mercapto-benzamide. Affinity molecules, such as antibodies, are capable of selectively binding to the predetermined biological substance to be detected, such as a particular antigen, etc. In a twenty-sixth preferred embodiment, the nanoparticles are attached to a polishing or rectifying pad, such as a mechanical chemical polishing pad used to polish semiconductor devices. In - In this embodiment, semiconducting, metallic or ceramic nanoparticles are attached to the grinding or polishing surface of the polishing pad, such as a cloth, plastic, ceramic or paper pad. Nanoparticles having the same composition as the layer being polished or rectified are preferred. For example, nanoparticles of silicon, silicon dioxide and silicon nitride, respectively, can be used on polishing pads used to polish silicon, silicon dioxide and silicon nitride, respectively, because these nanoparticles are not adulterants for the layer being polished. polish The specific examples of the nanoparticles made according to the methods of the preferred embodiments of the present invention will now be described. These specific examples are provided for illustration only and should not be considered as limiting the scope of the invention. Example 1: manufacture of silicon nanoparticles by the method of the first preferred embodiment. A silicon pellet was milled by a fixed 0.1 micron (1000 nm) sized abrasive diamond film (purchased from South Bay Technology, Inc.) located on a polishing plate for 3 minutes with water as the particulate dispersant. The water was emptied onto the film during grinding and was collected in a plastic container during grinding by placing the polishing plate inside the container. Figure 7 shows the particle size distribution of the silicon obtained in the water using the process described above. The particles have a peak size between 50 and 100 nm and a wide size distribution. Figure 8 shows the particle size distribution of the silicon obtained in water using the process described above and after 5 minutes of chemical attack in a solution of HF: H2O (1:50 by volume). This clearly shows that the small and large particles dissolve and the size distribution approaches.

- - For this process, the HF was added in a quantity mediated to the solution of Figure 7. Figure 9 shows the particle size distribution after the additional chemical attack during 5 minutes when adding HF: H20 (1: 50 by volume) in the solution of Figure 8. Figure 10 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF: H20 (1: 50 by volume) in the solution of Figure 9. The peak size of the nanoparticles decreased in Figures 9 and 10 compared to that in Figure 8. Figure 11 shows the particle size distribution of silicon in water after centrifugation of the solution of Figure 9 for 2 minutes and extracting 50% higher of the liquid. The particle size distribution approached and the peak size fell. Figure 12 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF.?NO3:CH3COOH(3:5:3 by volume) in the solution of Figure 10. Figure 13 shows the distribution of particle size after additional chemical attack for 5 minutes by adding HF: H2O (1: 50 by volume) in the solution of Figure 11. The peak particle size and the size distribution decreased in both cases. In this way, nanoparticles with a peak or average size of 25-60 nm and a size distribution of 10-30 nm could be obtained by selecting the appropriate etching and filtration steps. The particle size could be further reduced with additional etching and / or purification steps. Example 2: manufacture of silicon nanoparticles and a SiO2 cover (Le., Silicon core with a silica surface region) according to the second preferred embodiment. A silicon wafer was milled by a ball milling process for 48 hours and the powder was suspended in water. Figure 14 shows the initial particle size distribution of - silicon suspended in water using the process described above. The particle size distribution is very broad despite longer milling times compared to the first example (3 minutes). Figure 15 shows the particle size distribution of silicon obtained in water using the process described with respect to Figure 14 above and after 5 minutes of chemical attack in a solution of HF: H2O (1:50 by volume). For this process, the HF was added in measured quantity to the solution of Figure 14. The particle size distribution was significantly approximated Figure 16 shows the particle size distribution after the additional chemical attack for 5 minutes when adding HF: H2O (1: 50 by volume) in the solution of Figure 15. Figure 17 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF: H2O (1: 50 by volume) in the solution of Figure 16. The peak particle size and distribution was significantly approximated. Figure 18 shows the particle size distribution of silicon in water after centrifugation of the solution of Figure 17 for 2 minutes and extracting the upper 50% of the liquid. The peak particle size and distribution were significantly approximated. Figure 19 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF: H2O (1:50 by volume) in the solution of Figure 18. Figure 20 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF: H20 (1: 50 by volume) in the solution of Figure 19. The peak particle size and distribution were significantly approximated. Figure 21 shows the particle size distribution after adding NaOH in the solution of Figure 20 to change the pH from 5.5 to 8. The silicon particles were oxidized to form core-shell Si / SiO2 nanoparticles by this process and the solution appeared whitish. Example 3: manufacture of Si02 nanoparticles using the method of the first preferred embodiment. A quartz (silica) plate was milled by a fixed 0.1 micron (1000 nm) sized abrasive diamond film (purchased from South Bay Technology, Inc.) for 3 minutes with water as a particulate dispersant. The water was emptied onto the film during grinding and was collected in a plastic container during grinding by placing the polishing plate inside the container. Figure 22 shows the particle size distribution of Si02 obtained in water using the process described above. Figure 23 shows the particle size distribution after 5 minutes of chemical attack in HF: H2O solution (1:50 by volume). The HF was added in measured quantity to the solution of Figure 22. Figure 24 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF: H2O (1: 50 by volume) in the solution of the Figure 23. Figure 25 shows the particle size distribution after the additional chemical attack for 5 minutes by adding HF: H2O (1:50 by volume) in the solution of Figure 24. The peak particle size and distribution is they approximated significantly by controlled chemical attack. Figure 26 shows the particle size distribution of silicon dioxide in water after centrifugation of the solution of Figure 25 for 2 minutes and extracting the upper 50% of the liquid. The peak particle size and the distribution were additionally approximated. The foregoing description of the invention has been presented for purposes of illustration and description. This is not intended to be exhaustive or to limit the invention to the precise form described, and modifications and variations are possible in light of the above teachings or can be acquired from the practice of the invention. The drawings and description were selected in order to explain the principles of the invention and its practical application. It is proposed that the scope of the invention be defined by the claims appended hereto and their equivalents. All publications and applications for patents and patents cited in this specification are incorporated herein by reference in their entirety.

Claims (52)

1. CLAIMS 1. A plurality of nanoparticles having a metal oxide or semiconductor oxide surface region and a metal or semiconductor core region.
2. 2. The nanoparticles of claim 1, wherein: the nanoparticles contain a transition region located between the surface region and the core region; and the ratio of oxygen to metal or semiconductor in the transition region is the maximum adjacent to the surface region and gradually decreases toward the core region.
3. 3. The nanoparticles of claim 1, wherein the core region does not contain oxygen atoms or contains trace amounts of oxygen atoms.
4. 4. The nanoparticles of claim 3, wherein the nanoparticles comprise: a semiconductor core region of Si, Ge, SiGe, ll-VI, IV-VI or III-V; and a surface region of SiO2 oxide GeO2, I I-VI, IV-VI or III-V.
5. 5. The nanoparticles of claim 4, wherein the nanoparticles comprise: a Si core region; A surface region of SiO2; and a transition region of SiO2 rich in silicon, where x varies from 2 adjacent to the surface region to approximately zero adjacent to the core region.
6. The nanoparticles of claim 5, wherein the Si core regions of the nanoparticles are uniformly mixed with a Group III or Group V adulterant.
7. The nanoparticles of claim 3, wherein the nanoparticles comprise: metal core region; and a metal oxide surface region.
8. 8. The nanoparticles of claim 7, wherein the nanoparticles comprise: an Al core region; a surface region of AI2? 3; and an aluminum-rich AIOx transition region, wherein x varies from 3/2 adjacent to the surface region to approximately zero adjacent to the core region.
9. 9. The nanoparticles of claim 1, wherein the average size of the nanoparticles is from 2 to 100 nm with a size distribution of 10 to 25%.
10. The nanoparticles of claim 1, wherein the nanoparticles have an average size between about 2 nm and about 100 nm with a standard deviation of size of less than 60 percent of the average nanoparticle size measured by the photonic correlated spectroscopy method (PCS).
11. The nanoparticles of claim 10, wherein the nanoparticles are capable of being suspended in water without substantial agglomeration and substantial precipitation on the surfaces of the container for at least 30 days.
12. The nanoparticles of claim 1, wherein: the nanoparticles are suspended in a solution, suspension or mixture, or the nanoparticles are located on a solid substrate or in a solid matrix.
13. The nanoparticles of claim 1, wherein the nanoparticles are made by providing semiconductor or metal nanoparticles in an oxidizing solution, and oxidizing the semiconductor or metal nanoparticles in the oxidation solution.
14. 14. A plurality of uniformly blended nanoparticles having an average size between about 2 nm and about 100 nm with a size standard deviation of less than 60 percent of the average nanoparticle size determined by the photon correlated spectroscopy (PCS) method.
15. The nanoparticles of claim 14, wherein the nanoparticles have an average size between about 2 nm and about 10 nm with a standard size deviation of between about 10 and about 25 percent of the average nanoparticle size determined by the method of Photon correlated spectroscopy (PCS).
16. 16. The nanoparticles of claim 14, wherein the nanoparticles comprise semiconductor nanoparticles.
17. 17. The nanoparticles of claim 18, wherein the nanoparticles comprise silicon nanoparticles uniformly mixed with Group II or Group V adulterants.
18. 18. The nanoparticles of claim 17, wherein each of the uniformly mixed nanoparticles have a concentration of adulterant that varies by less than 5% throughout its volume.
19. 19. The nanoparticles of claim 18, wherein the uniformly mixed nanoparticles have an average adulterant concentration that varies by less than 5% between the nanoparticles.
20. The nanoparticles of claim 14, wherein the nanoparticles are capable of being suspended in water without substantial agglomeration and substantial precipitation on the container surfaces for at least 30 days.
21. 21. The nanoparticles of claim 14, wherein the nanoparticles comprise nanoparticles of mixed metal or metal oxide.
22. 22. The nanoparticles of claim 21, wherein the nanoparticles comprise uniformly alloyed metal nanoparticles.
23. 23. The nanoparticles of claim 21, wherein the nanoparticles comprise uniformly mixed ceramic metal oxide or silica nanoparticles.
24. 24. The nanoparticles of claim 23, wherein the nanoparticles comprise phosphorus nanoparticles of ceramic metal oxide uniformly mixed with activating ions.
25. 25. The nanoparticles of claim 21, wherein each of the uniformly mixed nanoparticles has a concentration of adulterant that varies by less than 5% throughout its volume.
26. 26. The nanoparticles of claim 21, wherein the uniformly mixed nanoparticles have an average concentration of adulterant that varies by less than 5% between the nanoparticles.
27. 27. A manufacturing article comprising the nanoparticles of claim 14, selected from the group consisting of: (a) the polishing mixture comprising a polishing mixture fluid and the nanoparticles of claim 14 in the mixing fluid; (b) a device that contains a hard or wear resistant coating, wherein the cover comprises the nanoparticles of claim 14, located on at least a portion of the device; (c) an ultra low porosity material having a porosity below 10 volume percent comprising a solid matrix and the nanoparticles of claim 14 incorporated in the matrix; (d) a filter comprising the compressed nanoparticles of claim 14; (e) a paint comprising a liquid base and the nanoparticles of claim 14; (f) an article of clothing or footwear containing a moisture barrier, wherein the moisture barrier comprises a layer of nanoparticles of claim 14, located on at least one surface of the article; (g) an environmental detector comprising a radiation source and a matrix material containing the nanoparticles of claim 14; (h) a light emitting device comprising light emitting nanoparticles of claim 14; (i) an organic light-emitting diode comprising an organic light-emitting material in a nanoparticle matrix of claim 14, a first electrode and a second electrode; 0) a lamp, comprising a cover, a radiation source located on the cover, and a nanoparticle layer of claim 14 located on at least one surface of the cover, wherein the nanoparticles absorb the radiation emitted by the source of radiation and emit visible light; (k) a magnetic data storage device comprising a magnetic field source, a data storage medium comprising the nanoparticles of claim 14; and a photodetector that detects the radiation emitted from the nanoparticles in response to the application of a magnetic field by the magnetic field source; (I) a magnetic storage medium comprising a magnetic material and the nanoparticles of claim 14; (m) an optical storage medium comprising a substrate, and the nanoparticles of claim 14 located in predetermined areas of the substrate, so that the first areas of the substrate contain the nanoparticles while the second areas of the substrate do not contain the nanoparticles; (n) an optical system, comprising at least one microménsula, and the light-emitting nanoparticles comprising the nanoparticles of claim 14 located on a tip of at least one microménsula; (o) an optical switch, comprising light-emitting nanoparticles comprising the nanoparticles of claim 14, and a magnetic field source that is adapted to quench the radiation emitted by the nanoparticles when it provides a magnetic field adjacent to the nanoparticles; (p) an ink comprising a liquid ink and the nanoparticles of claim 14; and (q) a cleaning composition comprising a cleaning fluid containing the nanoparticles of claim 14.
28. 28. The article of claim 27, wherein: the device (b) comprises at least one of a tool, a drill , a turbine blade, a gear and a cutting apparatus; the liquid base of the paint (e) evaporates after being applied to a surface, so that the nanoparticles of claim 14 provide a color to the surface; the moisture barrier of clothing or footwear (f) generates heat when exposed to sunlight or traps the heat emitted by a body; the nanoparticle layer in the lamp (j) contains nanoparticles that emit light of different color, so that the combined light emission of the nanoparticles appears as white light to a human observer; and the nanoparticles in the magnetic storage medium (l) comprises barrier layers located in the magnetic material so that the barrier layers form domain walls in the magnetic material or the medium (I) further comprises a substrate containing the nanoparticles mixed with atoms of the magnetic material, so that each of the nanoparticles is adapted to store a bit of data.
29. 29. A method for making nanoparticles, comprising: providing a bulk material; grind the bulk material to a powder that has particles of a first size; providing the powder having particles of a first size in a solution; and providing a chemical etching liquid to the solution to chemically attack the particles of the first size to nanoparticles that have a second size smaller than the first size.
30. 30. The method of claim 29, wherein the material in the mass comprises a semiconducting mass material.
31. 31. The method of claim 30, wherein the bulk material comprises a uniformly mixed semiconducting mass material.
32. 32. The method of claim 30, wherein the dough material comprises at least a portion of a silicon wafer uniformly mixed with suitable Group III or Group V adulterants.
33. The method of claim 29, wherein the bulk material comprises a ceramic bulk material.
34. 34. The method of claim 33, wherein the ceramic mass material is selected from the group consisting of silica, alumina, titania, zirconia, zirconia stabilized with yttria, tria, ceria, spinel, and tantalum pentaoxide.
35. 35. The method of claim 29, wherein the bulk material comprises a pure metal or a metal alloy.
36. 36. The method of claim 29, wherein the method is conducted at a temperature below 100 C.
37. 37. The method of claim 29, wherein the grinding step comprises placing a piece of the material in bulk on a abrasive film and move the piece and the abrasive film in relation to each other to grindd Z. 30 the mass material to a powder.
38. 38. The method of claim 37, further comprising washing the powder with water to collect the powder.
39. 39. The method of claim 29, wherein the grinding step comprises grinding balls of bulk material.
40. 40. The method of claim 29, wherein: the solution comprises an aqueous solution; and the chemical etching liquid comprises HCl, KOH, HF or NaOH.
41. 41. The method of claim 29, wherein the solution comprises an oxidant solution that oxidizes at least one surface of the semiconductor or metal nanoparticles to form semiconductor or metal oxide surface regions on the nanoparticles.
42. 42. The method of claim 29, further comprising incorporating the nanoparticles into a manufacturing article.
43. 43. A method for making nanoparticles, comprising: providing semiconductor or metal nanoparticles in an oxidizing solution; and oxidizing the semiconductor or metal nanoparticles in the oxidant solution to form a semiconductor oxide or metal oxide surface region on the respective semiconductor or metal nanoparticles.
44. 44. The method of claim 43, wherein the semiconductor or metal nanoparticles comprise silicon nanoparticles.
45. 45. The method of claim 43, wherein the semiconductor or metal nanoparticles comprise nanoparticles of pure metal or metal alloys.
46. 46. The method of claim 43, further comprising grinding a metal or semiconductor material in bulk to form the semiconductor or metal nanoparticles before providing the semiconductor or metal nanoparticles to the oxidation solution.
47. 47. The method of claim 43, wherein the semiconductor oxide or metal oxide nanoparticles comprises: a semiconductor oxide or metal oxide surface region a semiconductor or metal core region; and a transition region located between the surface region and the core region; wherein the ratio of oxygen to metal or semiconductor in the transition region is the maximum adjacent to the surface region and decreases gradually towards the core region.
48. 48. A method for making semiconductor nitride or metallic nitride nanoparticles, comprising: providing semiconductor or metal nanoparticles in a nitridant solution; and nitrifying the semiconductor or metal nanoparticles in the nitrurant solution to form a semiconductor nitride or metal nitride surface region over the respective semiconductor or metal nanoparticles.
49. 49. A polishing or grinding pad comprising a pad material and nanoparticles bonded to the surface of the pad material.
50. 50. The pad of claim 49, wherein the nanoparticles comprise nanoparticles of silicon, silicon oxide or silicon nitride.
51. 51. A mechanical chemical polishing method, comprising: placing a device for polishing on a first surface of a polishing pad having nanoparticles attached to the first surface; provide a chemical-mechanical polishing fluid on the first surface of the polishing pad; and chemically-mechanically polishing the device
52. 52. The method of claim 51, wherein the polishing fluid contains nanoparticles and is provided to the pad prior to placing the device on the first surface of the pad.