Thin Oxide Films for Miscellaneous Applications
Research and Development of Oxidized Thin Films of Various Functionality, Particularly, for Photovoltaic, Optoelectronic and Gas Detection Applications
Tech Area / Field
- MAT-ELE/Organic and Electronics Materials/Materials
- PHY-SSP/Solid State Physics/Physics
3 Approved without Funding
Institute of Physics and Technology, Kazakstan, Almaty
- Kazakh National University / Center of Physical and Chemical Methods of Analysis, Kazakstan, Almaty
- Nagasaki University, Japan, Nagasaki\nUniversity of Surrey, UK, Guildford\nUniversity of Michigan, USA, MI, Ann Arbor
Project summaryThe project goal is research and development of nanostructured oxidized thin films of various functionality assigned for use in photovoltaics, optoelectronics, for obtaining of sensors, wear-resistant and corrosion-resistant materials etc. The project is intended to the best utilization and ensuring long-term maintenance of modern equipment recently granted to Regional Experimental Center for Thin Film Research opened at the Institute of Physics and Technology under the US Civilian Research and Development Foundation RESC Major Equipment Program Award # KR1-990.
The main objectives of the project are:
– study of origin and structure of micro- and nanoclusters in solids, their physical properties and conditions of controlled and reproducible formation;
– study of defect microstructure and electronic properties of semiconducting and insulating oxidized thin-film structures prepared by using various methods and investigation of technological conditions effects on properties of thin films;
– study of electrical and strength characteristics as well as gas sensitivity of different thin-film coatings and development of technological methods for thin film preparation;
– study of regularities and mechanisms of corrosive hydrogenation of metals, study of corrosion films formation on their surfaces, determination of kinetic characteristics of these processes and their dependencies on various factors.
The project team has a broad experience in the field of materials research and development. Some of recent results are wide known: detection and study of phenomena of hydrogen passivation of defects and impurities in silicon and silicon-based devices, detection and identification of IR active complexes of hydrogen with impurities and defects in silicon, detection and study of shallow donor states in hydrogen-implanted silicon, detection of a number of EPR active centers labeled in international classification as AA-centers (AA means Alma-Ata city), detection of a number of new bistable and metastable complexes in silicon, development of scientific bases of semiconductor doping with low-energy ions and radiation technology for preparation of photovoltaic devices and various gas sensors, study of a radiation creep of metastable alloys and embrittlement of steels at grain-boundary creeping, development of new, nonconventional ways for control of properties of solids. Recently at IP&T a new phenomena of low-temperature, hydrogen-enhanced migration of impurity atoms in silicon was discovered.
The project is intended to carrying out basic and applied researches on a topical problem of control of micro- and nanostructures properties. Here it is necessary to note that the transition to nanocrystalline state is frequently accompanied by change in optical activity in a spectral range practically relevant for optoelectronics, by appearing of anisotropic properties, for example, sharp difference in resistance of a film in different directions, by increase of a microhardness, wear-resistance, corrosion-resistance and change of other properties (for example, modulus of elasticity and plasticity). This abrupt change of properties of solids attracts in both basic and applied aspects.
It is expected to get data on dependence of physical-chemical and mechanical properties of thin films on crystal grains sizes, which is not systematically studied up to now. The size effect phenomena are not quite understood especially those relating to many thin film deposition methods such as DC and RF magnetron sputtering, ion beam assisted deposition etc., which are used for obtaining of advanced nanocrystalline thin-film materials.
In the field of corrosion research, the expected results are understanding of influence of mass transfer and properties of new metal surface phase on regularities of corrosion film formation, determination of kinetic characteristics of processes of hydrogen emission at the metal surface and bulk metal hydrogenation, determination of dependence between surface states and hydrogenation processes.
The project results will be important for physics of thin films, of semiconducting materials and for whole materials science and technology and will promote more understanding of micro- and nanoclusters behavior in solids, their formation and properties control. The study of ion beam assisted deposition and ion mixing will enable to get more understanding of intensive ion implantation processes. The study of microstructure of defect in semiconductor and oxidized thin films will enable to determine a spectrum of possible microscopic configurations and will promote development of the solid state theory. Besides the basic science importance, these problems have also significant applied value.
It is expected that the study of optical, electrical, mechanical, chemical and other properties of oxidized thin films especially of nanostructured films will enable to prepare light emitting structures for silicon-based micro- and optoelectronics, antireflective and conductive layers for photovoltaic systems, sensing elements of various detecting devices.
It is very topical for Kazakstan and Central Asia countries to manufacture various low-cost sensors, especially gas sensors and sensors for control of grain and cotton humidity, air pollution, level of combustible and noxious gases in private life, chemical, mining, food-processing industry etc. Considerable economic impact may be given by results on improving of wear-resistance and corrosion-resistance of tool and construction materials, on development of low-cost solar cells prepared using thin-film technologies. The successful implementation of the project will enable project participants to produce thin-film technologies that will respond to Kazakhstan’s national priorities to develop domestic manufacture of various equipment and spare parts, in particular, for needs of companies working in export branches and in agriculture.
The project will undoubtedly respond to the ISTC goals and objectives:
– Weapon scientists and engineers from IP&T and CPCMA will get the opportunity for peaceful basic and applied research activity in the field of physics and chemistry of thin films widely used for civil production.
– Nanosized thin films and structures researches are now at the leading edge of science and engineering and will undoubtedly assist to integration of scientists from IP&T and CPCMA into the international scientific community.
– The project is intended to basic and applied researches and development of thin-film technologies for use in micro- and optoelectronics, for obtaining of wear-resistant and corrosion-resistant coatings. For Kazakstan with ecology exposed by various deleterious man-caused effects, it is of great importance to develop thin films for photovoltaics and sensing devices used in petrochemical, metallurgical, transport and other branches for control of level of environment pollution by toxic and combustible gases and other wastes.
– The project has potential to contribute to conversion efforts of former weapon companies in Kazakstan that are interested to produce science-based competitive products for civil needs. Methods for thin film coatings obtaining and improvement of wear-resistance and corrosion-resistance, expected to be developed in the course of project implementation, may be utilized by these companies to manufacture various equipment, tools, constructions etc.
Following activities are planned in the course of project implementation:
– Development of methods for oxidized thin films preparing by using magnetron sputtering and ion beam assisted deposition.
– Study of structure and properties of passivating, conducting, antireflective and optical active thin films.
– EPR study of structure and properties of defects in thin films and at thin film/substrate interfaces.
– Study of phase-boundary interaction processes at metal – liquid phase interfaces, study of corrosive thin films formed during these processes, study of interactions of emitted hydrogen with metal surface and study of mass transfer in reacting phases.
– Development of technological procedure for preparing of semiconductor thin films used for gas sensing devices and study of physical-chemical properties of these films in order to improve their gas sensitivity and selectivity.
It is expected that foreign collaborators will:
– assist in information exchange in the course of project implementation, in consultations and joint correction of project tasks if it will be necessary;
– provide comments to the technical reports (quarterly, annual, final etc.) submitted by project participants to the ISTC;
– help to perform coordinated experiments with using of certain equipment of collaborator especially with using of transmittance electron microscope if it will be available;
– participate, in case of need, in cross-checks of results obtained in the course of project implementation;
– participate in technical monitoring of project activities performed by ISTC staff (this has to be preliminary coordinated with collaborator);
– assist project participants to attend at international meetings and to search foreign partners for further project development;
– assist in conduction of joint seminars and workshops.
The following approaches and methods will be as applied to achieve the project goals:
1. Nanostructured thin films will be prepared by using the methods of magnetron sputtering and ion beam assisted deposition. After deposition of thin films, thermal treatments including rapid thermal processing will be carried out.
2. Structure, phase and elemental composition, optical and electrical properties of thin films will be characterized by using of TEM, X-ray diffraction at sliding beam angles, SIMS, Auger-spectroscopy, IR and visible spectroscopy, PL, ellipsometry, probe resistivity measurement method, Hall effect etc.
3. The influence of nanocrystals sizes on optical, magnetic, electrical and other characteristics of thin films prepared by using of magnetron sputtering and ion beam assisted deposition will be studied.
4. Sensitivity and selectivity of thin-film gas sensors will be characterized using gas mixtures calibrated by high sensitive gas chromatography system НР6890 with mass-selective detector produced by Hewlett-Packard Company.
5. The study of kinetics of hydrogen emission on a metal will be carried out by using methods of chronovoltamperometry, chronopotentiometry, rotating attracted-disk electrode and other methods used in case of need. For calculation of parameters, the earlier offered electrochemical method of measurement of rate of dissolved hydrogen transport to the back side of a metallic membrane with its emission on the opposite side will be used and improved.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.