Gamma radiation exposure of MCT diode arrays

Investigations of electrical properties of long-wavelength infrared (LWIR) mercury cadmium telluride (MCT) arrays exposed to gamma-radiation have been performed. Resistance-area product characteristics of LWIR n{+}-p photodiodes have been investigated using microprobe technique at T=78 K before and after an exposure to various doses of gamma-radiation. The current transport mechanisms for those structures are described within the framework of the balance equation model taking into account the occupation of the trap states in the band gap.Comment: 11 pages, 4 figures, submitted to Semiconductor Science and Technolog

IR region challenges: Photon or thermal detectors? Outlook and means

Infrared (IR) detectors play now an increasing role in different areas of human activity (e.g., security and military applications, tracking and targeting, environmental surveillance, fire and harvest control, communications, law enforcement, space surveillance of the Earth, medical diagnostics, etc.). Discussed in the paper are issues associated with the development and exploitation of up to date basic IR radiation detectors and arrays. Recent progress of basic for applications focal plane arrays (FPAs) that has rendered significant influence on infrared imaging is analyzed, and comparison of FPA detector performance characteristics is described with account of operational conditions and performance limits

High intensity study of THz detectors based on field effect transistors

Terahertz power dependence of the photoresponse of field effect transistors, operating at frequencies from 0.1 to 3 THz for incident radiation power density up to 100 kW/cm^2 was studied for Si metal-oxide-semiconductor field-effect transistors and InGaAs high electron mobility transistors. The photoresponse increased linearly with increasing radiation power up to kW/cm^2 range. The saturation of the photoresponse was observed for all investigated field effect transistors for intensities above several kW/cm^2. The observed signal saturation is explained by drain photocurrent saturation similar to saturation in direct currents output characteristics. The theoretical model of terahertz field effect transistor photoresponse at high intensity was developed. The model explains quantitatively experimental data both in linear and nonlinear (saturation) range. Our results show that dynamic range of field effect transistors is very high and can extend over more than six orderd of magnitudes of power densities (from 0.5 mW/cm^2 to 5 kW/cm^2)

Photosensitive heterostructures CdTe-PbTe prepared by hot-wall technique

Hot-wall technique has been used for preparation of CdTe-PbTe heterostructures. BaF₂ single crystals served as substrates. Electrical, photoelectric properties as well as noise spectra were investigated. Heterostructures exhibit photosensitivity up to room temperatures in the middle infrared (IR) region. In the heterostructures investigated at room temperature the 1/f noise is observed at frequencies much less compared to those ones observed in PbSe photoresistors (f = 3000 Hz) for the same IR region. Carrier transport mechanisms and band diagram of the heterostructures are briefly discussed

Energy spectrum, density of states and optical transitions in strongly biased narrow-gap quantum wells

We study theoretically the effect of an electric field on the electron states and far-infrared optical properties in narrow-gap lead salt quantum wells. The electron states are described by a two-band Hamiltonian. An application of a strong electric field across the well allows the control of the energy gap between the two-dimensional (2D) states in a wide range. A sufficiently strong electric field transforms the narrow-gap quantum well to a nearly gapless 2D system, whose electron energy spectrum is described by linear dispersion relations \epsilon_{\sigma} (k) ~\pm (k-k_{\sigma}), where k_{\sigma} are the field-dependent 2D momenta corresponding to the minimum energy gaps for the states with spin numbers \sigma. Due to the field-induced shift of the 2D subband extrema away from k=0 the density of states has inverse-square-root divergencies at the edges. This property may result in a considerable increase of the magnitude of the optical absorption and in the efficiency of the electrooptical effect.Comment: Text 18 pages in Latex/Revtex format, 7 Postscript figure

Ключевые направления инновационного развития экономики России с учетом опыта инновационной деятельности интегрированных корпоративных структур

ARTICLE RETRACTEDThe article deals with the problems and the key directions of The article deals with the problems and key directions of innovative development of the Russian industry in connection with the need to reduce the dependence of the national economy on the situation on world commodity markets, as well as to create the conditions and incentives for the introduction and modern technologies development, improving energy and environmental efficiency of the economy and productivity for the development of economic sectors and industries, producing goods with high added value for the implementation of innovative projects and in general - to upgrade the socio-economic system of the country.The following statement is given: the development of innovative high-tech and knowledge-intensive industries must ensure import substitution products at the first stage, primarily in the militaryindustrial complex, and in the future - export-oriented competitive product.The article analyzes the experience of innovative activity of the integrated corporate structures with the participation of the state in the following areas: the integration of the industrial and financial capital; the concentration of capital (through the merger and acquisition of enterprises, strategic alliances); diversification of forms and fields of activity; globalization of activities (creation of subsidiaries in the most attractive countries and working on promising markets); capital internationalization (through the creation of transnational companies).On the basis of generalization of global corporate management experience in the state corporations the article analyzes key conditions and factors that determine the efficiency of the state-owned companies as a whole: a clear statement of goals and objectives of the state as the owner, whose interests go beyond the usual business purposes; fixing of these goals and objectives in the regulations, in the concepts and programs of long-term socioeconomic development of the country, in special agreements between the government and public sector enterprises, as well as in the statutes, in the policy and budgetary documents of state corporations; the creation of state corporations administration system that allows to carry out the separation of the control and management functions, to ensure coherence and consistency of the implementation of the asset management policy, the uniformity of the rules of management of state property on the basis of common rules; harmonization of interests of the state and private investors, their documentary fixation (for corporate plans, agreements between the parties, etc.) in order to limit undue state interference in the activities of state-owned companies, on the one hand, and protection from lobbying strain - on the other hand; increasing business transparency, which is the foundation of good governance; the establishment of effective operational management systems, including goal setting and planning, reporting, monitoring, control and evaluation of companies, risk management and information disclosure.СТАТЬЯ ОТОЗВАНА В статье рассматриваются проблемы и ключевые направления инновационного развития промышленности России в связи с необходимостью уменьшения зависимости национальной экономики от ситуации на мировых рынках сырья, а также в целях создания условий и стимулов для внедрения и развития современных технологий, повышения энергетической и экологической эффективности экономики и производительности труда, для развития отраслей экономики и производств, выпускающих продукцию с высокой долей добавленной стоимости, для реализации инновационных проектов и в целом – для модернизации социально-экономической системы страны. Выдвигается и обосновывается положение о том, что инновационное развитие высокотехнологичных и наукоемких отраслей промышленности должно обеспечить на первом этапе импортозамещение продукции, в первую очередь, в оборонно-промышленном комплексе, а в дальнейшем – экспортную ориентацию конкурентоспособной продукции. В статье содержится анализ опыта инновационной деятельности интегрированных корпоративных структур с участием государства по следующим основным направлениям: интеграция промышленного и финансового капитала; концентрация капитала (через слияние и поглощение предприятий, создание стратегических альянсов); диверсификация форм и сфер деятельности; глобализация деятельности (создание дочерних предприятий в наиболее привлекательных странах и работающих на перспективных рынках); интернационализация капитала (через создание транснациональных компаний). На основе обобщения мирового опыта корпоративного управления в государственных корпорациях в статье формулируются ключевые условия и факторы, определяющие эффективность функционирования госкомпаний в целом: четкая формулировка целей и задач государства как собственника, интересы которого выходят за рамки обычных целей коммерческой деятельности; фиксация этих целей и задач в нормативных документах, в концепциях и программах долгосрочного социально-экономического развития страны, в специальных соглашениях между государством и предприятиями госсектора, а также в уставных документах, в программных и бюджетных разработках самих госкорпораций; создание системы администрирования госкорпораций, позволяющей осуществить разделение контрольных функций и функций управлений, обеспечить согласованность и последовательность реализации политики управления имуществом, единообразие правил управления госсобственностью на основе единого регламента; согласование интересов государства и частных инвесторов, их документальная фиксация (в корпоративных планах, в договорах между этими сторонами и т.д.) с целью ограничения неоправданного вмешательства государства в деятельность госкомпаний, с одной стороны, и защиты от лоббистских деформаций – с другой; повышение прозрачности бизнеса, что является основой эффективного управления; создание эффективных систем оперативного управления, в том числе системы целеполагания и планирования, отчетности, мониторинга, контроля и оценки деятельности предприятий, системы управления рисками и раскрытия информации

Sub-THz nonresonant detection in AlGaN/GaN heterojunction FETs

Abstract. Un-cooled AlGaN/GaN-based heterojunction field-effect transistors (HFET) designed on sapphire (0001) substrates were considered as 140 GHz direct detection detectors without any specially attached antennas. The noise equivalent power (NEP) of these detectors was ~