Nanotechnology for obtaining nanostructurized materials and nanocomposites (variants)

Description:

The invention relates to electronics, in particular to nanotechnologies for obtaining nanostructured materials and nanocomposites.

The invention relates to electronics, in particular to nanotechnologies for obtaining nanostructured materials and nanocomposites.

Various nanotechnologies and methods for obtaining nanostructured materials, nanocomposites and devices created from them are known: for example, nanotechnology for non-stoichiometric and stoichiometric nanocomposite materials, obtained by mixing and pressing powders of twice as many oxide and crystal compounds. TiO₂, CuO, BaTiO₃, NiFe₂A₄, TiC, SnO₂, ZnS, GaN, NiFe_xA_y, Ba_xTi_yA_z and others [1, 2], nanotechnology for electronic and optoelectronic devices [3], nanotechnology for reactive gas films [4], nanotechnology for electrochemical and energy devices [5], nanotechnologies and Rapid Thermal Processing (RTP) methods for processing silicon platelets [6].

These nanotechnologies have a number of shortcomings, including: firstly, to obtain high quality materials, they apply very sophisticated methods and expensive technological processes that cannot be used extensively; Secondly, these technologies use heat treatment in electric stoves, which leads to high energy costs; thirdly, the heat treatment used ensures the heating and pyrolysis of the chemical solutions deposited on the substrate without using the quantum effect of light, without modifying and improving the properties of the obtained materials; Fourth, these technologies are not quite illegible to obtain materials with certain properties, nanostructures and nanocomposites. Rapid photothermal processing (PFTR) is not used in all these nanotechnologies. In the nearest solution [6], rapid thermal processing (RTP) of silicon platelets is used in the presence of low oxygen concentration to determine the surface properties of the silicon wafer, the required silica doping level and the formation of silicon oxide sub-films, using - it is only the thermal effect of the action of light, the rapid heating, and not the photonic, quantum effect.

The problem solved by the invention is to diversify the functional possibilities of nanotechnologies, increase the efficiency of the formation of the properties of nanostructured materials and nanocomposites, the essential reduction of the cost of the technology of nanostructured materials and nanocomposites of semiconductors! nano-electronic and multifunctional.

The essence of the invention is that the nanotechnology of nanostructured materials and nanocomposites, according to the first embodiment, includes the deposition of chemical components on a substrate in the presence of ultraviolet rays. Then, rapid photothermal processing of materials obtained in vacuum or air, or in the gas chamber, for example, with oxygen, takes place.

Nanotechnology for obtaining nanostructured materials and nanocomposites, according to the second variant, includes the deposition of chemical components on a substrate in the presence of ultraviolet rays, and with the deposition of the chemical components the doped materials with at least one donor or acceptor impurity take place. Then the rapid photothermal processing of the materials obtained in vacuum or air, or in the gas chamber, for example, with oxygen, is performed.

Nanotechnology for obtaining nanostructured materials and nanocomposites, according to the third embodiment, includes depositing chemical components on a substrate in the presence of ultraviolet rays, following diffusion doping with at least donor or acceptor impurity, with rapid photothermal processing of the obtained materials or vacuum. in the air, or in the gas chamber, for example, with oxygen.

Nanotechnology for obtaining nanostructured materials and nanocomposites, according to variant four, includes depositing the chemical components on a substrate in the presence of ultraviolet rays, following diffusion doping with at least о impurity. The concentration of the impurities being maximum possible for the obtained material. Subsequently, the rapid photothermal processing of the obtained materials takes place under the conditions of reduction from the temperature of doping, to the ambient temperature in vacuum or air, or in the gas chamber, for example, with oxygen.

Light influences the chemical reactions and the technological processes, the deposition of the chemical components, the diffusion, the oxidation, by two decisive factors: the thermal factor - by the excitation of the phonons and the heating of the material; the quantum factor by exciting the electron system! and modification of material properties. By combining the actions of these two factors on a material, for example, a semiconductor, new effects and properties can be obtained, such as: decreasing the activation energy of the technological processes, increasing the diffusion coefficient of impurities, accelerating the physicochemical reactions and others. Namely, based on these effects, nanostructured materials and pure and doped nanocomposites with different impurities were obtained.

MD 2859 C2 09.09.2005

Nanotechnologies for obtaining nanostructured and nanocomposite materials include the action of both factors of influence of light: the thermal and the quantum factor, which provides a series of essential priorities over conventional technologies. At the same time, the functional possibilities of the technologies for the deposition of the subfirst films of materials by chemical, electrochemical, solgel, epitaxial, evaporated in vacuum etc. are expanded. Can be applied to obtain different materials, structures and devices of semiconductor !, semiconductor! oxides, metal oxides, other materials required for electronics (multi-functional devices, including sensors, micro-nano-optoelectronic devices, photonic and optical materials and devices, etc.);

These nanotechnologies ensure the improvement, modification and optimization of the fundamental properties of the materials, not only in the process of depositing the chemical components, but also after obtaining the materials subjected to the rapid photothermal processing, they ensure the formation and modification of the surface morphology, nanostructures and nanocomposites of semiconductor materials! oxides, metal oxides, other materials required for multifunctional devices, including sensors, micro-nano-opto-electronic devices, materials and photonic and optical devices.

Obtains a substantial economy of energy, materials and time. Under the influence of thermal and quantum factors, the activation energy of the technological processes (diffusion, oxidation, chemical reactions) decreases, the technological processes expand at higher speeds, at lower temperatures and at a lower time than conventional technologies.

The obtained results are confirmed by various tests of the properties of the obtained materials (ZnO, CuO, SiO₂): fundamental properties (electrical, photoelectric, optical, photoluminescent), structural properties (surface morphology, nanostructures, nanodefections) and material composition (chemical composition, doping with impurities). Semiconductor subfire films were obtained! oxides of various thicknesses (0.1 ... 5pm), with different resistivity values ​​(10 ... 10⁶Ωαη) and various spectra of photoluminescence.

Nanotechnology for nanostructured and nanocomposite materials includes the following steps:

- selecting the chemical components to obtain the required material, for example ZnO, CuO, SiO₂ etc .;

- Obtaining the suspension or aqueous solution of the necessary material with a certain composition M_XM_ZM_Z, where x, y, z represent the chemical elements, M - the quantity of the substance in moles;

- heating the suspension to the optimum temperature for the given substance (60 ... 97 ° C the interval for different substances);

- selecting and preparing the substrate with the plane of glass, or silicon (Si), or silicon oxide (SiO)₂/ Si), or other materials; cleaning the substrate surface with chemical solutions, by washing with distilled water and deionized water;

- successive immersion of the substrate in aqueous solution in the presence of ultraviolet rays, in a certain number of cycles, to obtain the required thickness of the film; following the rinsing of the films in deionized water and drying at 13O ... 17O ° C; for the semiconductor oxides о immersion allows to obtain a sub-layer with a thickness of approximately AL = 70 nm; so the film thickness (L) and the number of dives (N) can be calculated according to the formula L = ALx N.

The invention is explained by figures 1 ... 3.

In FIG. 1 shows the morphology of the non-doped ZnO film. The doped ZnO film obtained by the chemical method in the presence of ultraviolet light from the complex Na solution₂ZnO₂ with concentration 0.006M, duration 460s, at temperature 70 ° C. Rapid photothermal processing (PFTR) was performed at 550 ° C for 16 s in vacuo.

By optimizing the technological regime and the rapid photothermal processing, the composition, structure and morphology of the film surface can be controlled, obtaining nanostructured and / or nanocomposite materials.

In FIG. 2 shows the dependence of the resistivity of the ZnO film, doped with Sn. Sn doped ZnO film obtained by the chemical method in the presence of ultraviolet light from the ZnSO solution₄ NaOH - Na₂SnO3 with the respective concentrations 0.5M - 6M - 0.2M, dissolved in deionized water until the final concentration of 0.1 IM, duration 660s, at 86 ° C. Rapid photothermal processing (PFTR) was performed at 650 ° C for 20s in vacuo. By optimizing the technological regime and the rapid photothermal processing, the composition, structure, surface morphology and fundamental properties of the film can be controlled, obtaining nanostructured and / or nanocomposite materials.

It is found that following the rapid photothermal processing in vacuum, the resistivity of the material decreases from 18 Q.cm to 4 O.cm, while in air, conversely, the resistivity increases from 18 O.cm to 95 Ω.αη.

The decrease of the resistivity of the ZnO film in the vacuum PFTR result is explained by the decrease of the oxygen concentration following its evaporation from the surface of the ZnO granules, the increase

MD 2859 C2 2005.09.30 concentration of oxygen vacancies and electron concentration, reduction of separation and contact barrier between granules. Conversely, increasing the resistivity of the ZnO film in the PFTR result in air is motivated by the increase of the oxygen concentration in the ZnO films, the decrease of the concentration of oxygen vacancies and the concentration of electrons, the increase of the distance and the contact barrier between the granules. In the case of the reaction of oxygen with the atoms of the impurities present, complexes, nanocomposites and their compounds can be formed, forming nanostructured and nanocomposite materials.

In FIG. 3 shows the dynamics of the change of the spectral characteristic of the photoluminescence of the ZnO film, doped with aluminum, subjected to consecutive cycles of rapid photothermal processing in vacuum: 1,2 - initial, 3 - T = 500 ° C, t = 60s; 4 - T = 400 ° C, t = 60s; 5 - T = 450 ° C, t = 2xl0s; 6 - 500 ° C, t = 2xl 0s; 7 - 650 ° C, t = 2xl0s; the maximum Ei = 3.36eV ​​characterizes the photoemission between the valid and the conductive band, E₂= 3.33eV refers to the presence of the impurity of Al; the other maxims appear to dissipate Raman and various defects, such as vacancies, atoms in intersections, atomic complexes, nanocomposites and their compounds. It can be observed that with PFTR in vacuum different defects can be excluded from the crystalline refinery, intensifying the photoluminescence between the bands, Eg 3.36eV. and the one with the participation of the impurities of Al, E₂-3.3eV. In other experiments with TFTR air, or in the room with the presence of oxygen, the conditions of precipitation of the atoms of the given impurity and their reaction with oxygen, photoluminescence showed the presence of new defects - atomic complexes, nanocomposites and their compounds, which form the properties of the nanostructured material. and nanocomposite.