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- General Aspects of Photo- and Optoelectronics
- Focal Plane Arrays
- Quantum Well and Quantum Dot
- Photodectors
- Night Vision Systems
- Photoelectric Phenomena in Photodetectors
- Problems in the Technology of Photoelectronic Materials and Structures
- Requirements for Photodetectors and their characteristics Measuring
- Physical Properties of Materials for Thermoelectric Coolers
General Aspects of Photo- and Optoelectronics
Photoelectronics for a new generation of electron-optical equipment
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Results of the latest developments of technologies of photodetectors and photodetective assemblies including multi-element and matrix ones for IR-spectral range were discussed. Technologies for photodetectors based on CMT photodiodes for thermal imaging equipment operating on TDI mode (2×256, 4×288) or in a “staring” mode (384×288) as well as on the basis of photodiodes of indium antimonide received a large development effort. Technologies for manufacturing of high-speed photodetective assemblies for recording of pulse radiation in a wide interval of wavelengths from 0,3 to 11 μm for laser direction finding and metrology are actively developed. An analysis of up-to-date state of photoelectronics was carried out and main physics and technological problems of making photosensitive materials, photosensitive elements, cooling and image processing systems was observed.
Femto-attosecond photoelectronic imaging (the present state of the art and new trends)
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Basic advantages and limitations of ultrafast photoelectronic imagine are overviewed. Presented are recent experimental results on recording of Ti:sapphire laser radiation with 200-fs time resolution and 30-line pairs/mm spatial resolution. Some peculiarities in displaying of ultrafast optical events onto the photocathode with femtosecond precision are shortly mentioned. Special emphasis is given to creation of ultra high (10-100kV/mm) electrical field strength nearby the photocathode surfaces, as well as to manufacturing various types of femtosecond image converter tubes. To break the femtosecond barrier, a new technique for generation the attosecond bunches of tens keV electrons in quasistationary electromagnetic fields is proposed.
Analysis of physical and technological aspects of monolithic optoelectronic devices for on-board systems of remote sounding: I. Review of optoelectronic technologies
Oleg N. Ermakov
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With account of modern optoelectronics global trends brief review is presented for on - board (air - born and space - born) optoelectronic equipment, including monolithic optoelectronic devices designated for different purposes, including fiber - optic systems, navigation systems, focal plane arrays, visualization means. Different materials and technologies are used for this purpose. It's stressed that the problems of perspective on - board equipment can't be adequately solved without integrated optoelectronics and the main attention is paid for monolithic devices including those obtained by silicon on sapphire (SOS) technology. It's noted that earlier A2B6 and A3B5 compounds have been used correspondingly for photosensitive and light - emitting devices fabrication and now with the development of new technologies of quantum - confined photodetectors based on A3B5 and of efficient A2B6 - based light emitters applications boundary is more and more smearing. It's supposed that this trend will be enhanced allowing to fabricate new types of monolithic optoelectronic devices. It's stressed that one of the main problems of future optoelectronics will be the problem of heteroepitaxial growth of lattice mismatched device structures, the most promising substrates being silicon and sapphire.
Analysis of physical and technological aspects of monolithic optoelectronic devices for on-board systems of remote sounding: II. Experimental investigation
Oleg N. Ermakov
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With account of previous analysis of optoelectronic technologies for on - board systems experimental investigation results are presented for a number of structures (monocrystalline silicon, silicon on sapphire (SOS) structures, CdSe/SiO2/Si, GaN and InGaN on sapphire) illustrating the integrated optoelectronics possibilities for future very large-scale optoelectronic integrated circuirs realization. Data are presented for luminescence and photosensitivity characteristics of devices based on above-mentioned structures. Experimental results on electro - optic conversion characteristics in emitter - photodetector geometry are presented for silicon and sapphire substrate based devices. Different electroluminescence mechanisms in both forward and reverse biased mode with thermalized and hot carriers have been studied. It's shown that noticeable output signal can be obtained even using SOS - emitters. It's emphasized that the greatest potential for future integrated optoelectronics have sapphire substrate based devices. Physical and technological aspects of monolithic devices are considered including spectral characteristics, efficiency, resolution, cross stalk and pixel size limitations, low - current operation mode.
The solid state silicon photomultiplier for a wide range of applications
E. A. Georgievskya,
S. N. Klemin,
L. A. Filatov,
et al.
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The new type of photodetector - Silicon Photomultiplier (SiPM) is presented. The SiPM consists of the array (matrix) of p-n-junctions (~103 mm-2) joint together on a common silicon substrate. Each p-n-junction working in limited Geiger mode with a gain 106, but SiPM in whole is analogue detector, because the SiPM output signal is a sum of the signals from p-n-junctions fired by photons. The main SiPM features are described and its performance is compared with other photodetectors.
HgCdTe photodiodes current-voltage characteristics simulation
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Different current mechanisms in HdCdTe p-n junctions have been analyzed. Current-voltage characteristics of photodiodes in HdCdTe epitaxial layers formed by different epitaxial methods are measured and simulated. The numerical simulation of photodiodes current-voltage characteristics allows to evaluate HdCdTe material parameters and improve Focal Plane Arrays technology.
Focal Plane Arrays
Infrared focal plane arrays: state of the art and development trends
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Development and production of up-to-date IR focal plane arrays (FPA) in leading foreign countries are analyzed. Cadmium-mercury telluride (CMT) FPA are discussed for near, middle and long infra-red (IR) ranges including those ones operating in the time delay and integration (TDI) mode; FPA of indium antimonide, platinum silicide, lead selenide and telluride; quantum well infra-red photodetectos (QWIP) based on heterostructures of gallium arsenide/gallium-aluminum arsenide; uncooled FPA - microbolometric and pyroelectric; FPA of lead sulfide and indium-gallium arsenide; deep-cooled FPA of extrinsic silicon. Trends of further development of FPA for the thermal imaging systems of a new generation are discussed.
The 128x128 MWIR FPA on the base of epitaxial layer MCT grown by MOCVD
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MWIR 128x128 Focal Plane Array (FPA) performance has been investigated. FPA has been fabricated on the base of HgCdTe active layers grown on (111)B GaAs substrate by Metal Organic Chemical Vapor Deposition (MOCVD). Histograms and diagrams of photodiodes current, responsivity and detectivity have been plotted for FPA with cutoff value 5,1μm at T=200K.
The 128x128 and 288x384 InSb array photodetective assemblies for 3- to 5-um spectral range
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This paper explains the technologies used for high-performance Infrared Focal Plane Arrays (IRFPAs) based on InSb - p-MOS hybrid multiplexers. Mid-Wavelength Infrared (MWIR) photodiode arrays are fabricated using thin-base technology. Each photodiode array consists of 288x384-element p+-on-n diodes formed by Be+-implantation. The diodes had a typical zero-bias resistance of 0.5 GΩ. p-MOS Rolling Read Out Integrated Circuits (ROIC) with two outputs were used. Integrated Dewar Assembly type Integrated Stirling was used for cooling FPA. The Infrared Focal Plane Arrays had a typical Noise Equivalent Power (6÷8)10-13 W/pixel at 2•10-3 s storage time.
The 4x288 linear FPA on the heteroepitaxial Hg1-xCdxTe base
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x4×288 heteroepitaxial mercury-cadmium telluride (MCT) linear arrays for long wavelength infrared (LWIR) applications with 28×25 micron diodes and charge coupled devices (CCD) silicon readouts were designed, manufactured and tested. MCT heteroepitaxial layers were grown by MBE technology on (013) GaAs substrates with CdZnTe buffer layers and have cutoff wavelength λco ≈ 11.8 μm at T = 78 K. To decrease the surface influence of the carriers recombination processes the layers with composition changes and its increase both toward the surface and HgCdTe/CdZnTe boundary were grown. Silicon read-outs with CCD multiplexers with input direct injection circuits were designed, manufactured and tested. The testing procedure to qualify read-out integrated circuits (ROICs) on wafer level at T = 300 K was worked out. The silicon read-outs for 4×288 arrays, with skimming and partitioning functions included were manufactured by n-channel MOS technology with buried or surface channel CCD register. Designed CCD readouts are driven with four- or two-phase clock pulses. The HgCdTe arrays and Si CCD readouts were hybridized by cold welding indium bumps technology. With skimming mode used for 4×288 MCT n-p-junctions, the detectivity was about (formula available in paper) for background temperature Tb = 295 K.
LWIR 2x256 focal plane array for time delay and integration
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A FPA architecture and technology developed by RD&P Center ORION based on planar HgCdTe photodiode arrays and cooled silicon integrated readout circuits is presented. Photovoltaic detectors array made on mercury cadmium telluride (MCT) liquid phase epitaxy (LPE) layer and silicon readout circuits are linked by indium bumps on sapphire interconnection substrate. Cooled silicon readout circuits have been made by n-MOS technology with no TDI stages at focal plane. For 8-12 μm wavelength range detectivity is (5-10)×1010 cmW-1Hz1/2 for 2x256 FPA with two TDI elements.
The recent and prospective developments of cooled IR FPAs for double application at Electron NRI
V. A. Arutunov,
I. S. Vasilyev,
V. G. Ivanov,
et al.
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The recent and prospective developments of monolithic silicon IR-Schottky-barrier staring focal plane arrays (IR SB FPAs), photodetector assembly, and digital thermal imaging cameras (TICs) at Electron National Research Institute (Electron NRI) are considered. Basic parameters for IR SB FPAs with 256x256 and 512x512 pixels, and TICs based on these arrays are presented. The problems emerged while proceeding from the developments of IR SB FPAs for the wavelength range from 3 μm to 5 μm to the developments of those ones for xLWIR range are indicated (an abrupt increase in the level of background architecture). Possibility for further improvement in basic parameters of IR SB FPAs are discussed (a decrease in threshold signal power down to 0.5÷1.0•1013 W/element with an increase in quantum efficiency, a decrease in output noise and proceeding to Schottky barriers of degenerated semiconductor/silicon heterojunction, and implementation of these array parameters in photodetector assembly with improved thermal background shielding taking into consideration an optical structure of TIC for concrete application). It is concluded that relative simplicity of the technology and expected low cost of monolithic silicon IR SB FPAs with basic parameters compared with hybrid IR FPAs for the wavelength ranges from 3 μm to 5 μm and from 8 μm to 12 μm maintain large monolithic IR SB FPAs as a basis for developments of double application digital TICs in the Russian Federation.
The 1x384 hybrid linear infrared focal plane arrays on InAs MOS structure for spectrometric applications
V. M. Bazovkin,
N. A. Valisheva,
A. A. Guzev,
et al.
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Technology and design of linear 1x384 MIS photodetectors on InAs homoepitaxial substrate are developed. The experimental results on IR focal plane arrays (IR FPA) intended for rapid IR spectrometers with registration time 0,1 - 50 ms are presented.
Quantum Well and Quantum Dot
Quantum well and quantum dot infrared photodetectors: physics of operation and modeling
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We review recent studies of physical phenomena in quantum well infrared photodetectors (QWIPs), and some other QW and QD infrared devices and discuss their features. We show that the optimization of QWIPs, improvement of QDIPs, and creation of novel QWIP- and QDIP-based devices still requires an in-depth understanding of underlying physical effects.
Quantum well infrared photoconductors in infrared detectors technology
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The performance of quantum well infrared photodetectors (QWIPs) as compared to other types of semiconductor infrared (IR) detectors is examined utilizing the α/G ratio, where α is the absorption coefficient and G is the thermal generation. From the discussion results that long wavelength QWIP cannot compete with HgCdTe photodiode as the single device especially at higher temperature operation (> 70 K) due to fundamental limitations associated with intersubband transitions. However, the advantage of HgCdTe is less distinct in temperature range below 50 K because of the problems involved in an HgCdTe material (p-type doping, Shockley-Read recombination, trap-assisted tunneling, surface and interface instabilities). Due to the limited charge storage capacity of available readout circuits, a small photoconductive gain of QWIPs improves the noise equivalent difference temperature the sensor. The imaging performance of HgCdTe photodiodes and QWIP focal plane arrays can be said to be nearly equivalent when they are operated under their optimum conditions. Decision of the best technology is therefore driven by the specific needs of a system.
Photoelectrical characteristics of structures with nonrectangular quantum wells
Vladimir B. Kulikov,
I. V. Budkin
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For analytical description of multiple quantum well superlattices (MQW) main characteristics, for example, current-voltage characteristic (CVC), of the model of well with rectangular and symmetric walls is usually used. However, deviation of experimental characteristics of real MQW from analytical dependence make it possible to suppose, that real MQW are not rectangular and even not symmetric. The study of nonrectangular well influence on MQW characteristics would make it possible to determine how prevent from this influence by means of some modification introduction into growth process. In this report we present analytical description of CVC, field dependence of responsivity and signal/noise ratio for nonrectangular MQW. Analytical results are compared with experimental data. The possible ways to compensate nonrectangular wells influence is considered.
Responsivity of multiple quantum well structures grown by MOCVD at normal incidence
Vladimir B. Kulikov,
G. H. Avetisyan,
L. M. Vasilevskaya,
et al.
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The success in the area of multiple quantum well (MQW) devices development have been achieved mainly due to employment of molecular beam epitaxy (MBE). However at the same time for MQW growing metalorganic chemical vapor deposition (MOCVD) is used, because of its more high productivity. Our experience in MOCVD grown MQW and photodetectors based on them shows, that they have some differences from MBE grown analogs. These differences are: more high asymmetry of current-voltage characteristics, considerable responsivity at normal incidence. We believe, that differences mentioned above are related with features of MOCVD. In this report we present experimental results of responsivity investigation of MOCVD grown MQW, relation between experimental results and MOCVD grown MQW features is discussed.
Photoconductivity gain by Si p-n junction containing quantum dots
A. V. Dvurechenskii,
Ivan A. Ryazantsev,
Anatolii P. Kovchavsev,
et al.
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Si(Ge) junction (of p-i-n diode type) containing Ge of self-assembled quantum dots (SAQD). in a ~0,6 μm-thick near-surface layer were investigated. Analysis of photo- and electrophysical performances allowed to revel ~ 10-103 Iph(V) photocurrent gain by p-n junction at T=78K upon photodiode radiation with the photon energy corresponding to Si and Ge basic interband transitions. A model is proposed which assumes that SAQDs with a positive charge at T=78K turn out to be trapping centers for electrons/ At “forward” voltages on a photodiode (V>0,2), when the p-layer SAQDs are already partially outside the p-n junction, there takes place electron capture on SAQDs as on adhesion centers under conditions of photocarrier optical generation in Si(Ge). In this case, excess concentration of the p-layer electrons forming exsiton-type bound states with quantum dots leads to lowering the p-n junction potential barrier and photocurrent amplification.
3- to 5-um InGaAs/AlGaAs QWIP heterostructure growth by metal organic chemical vapor deposition
I. V. Budkin,
P. V. Bulaev,
L. M. Vacilevskay,
et al.
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InGaAs semiconductor heterostructures with multiple quantum wells for large-scale photodetectors on 3-5 spectral range were grown by low pressure metalorganic chemical vapor deposition. Growth conditions were optimized to obtain highly uniform heterostructures which can be used for producing of photodetector arrays. Growth temperature was 750 °C, pressure - 60 torr. Test photodetectors showed detectivity D=5,65×109sm•Hz1/2•W-1 at the spectral sensitivity maximum wavelength 5.2 μm at measurement temperature 77 K. These results demonstrate potential possibility to use InGaAs/ AlGaAs heterostructures for manufacturing of large-scale photodetector arrays on 3-5μm spectral range. The ways of further photodetector parameters improvement are suggested.
Special features of noise measurement of photosensitive quantum well structures
A. I. Khatountsev,
V. P. Kotov,
I. V. Budkin
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No abstract available.
Photodectors
Infrared photodetector on the basis of low-dimensional structure
E. Huseynov,
V. Salmanov
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The variant of the SPRITE-type device on the basis of structure with quantum wires is considered. Technological principles of creation such MCT photodetector have been considered and same photoelectric performances of the device have been estimated.
Properties of Schottky-barrier p-CdxHg1-xTe structures with metal-tunnel transparent dielectric
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Potential barriers in Schottky diodes with a metal-tunnel transparent dielectric based on CdxHg1-xTe (CMT) with x~0.2 have been studied. We used In, Tn, Al and Cr as metal barriers. Superthin dielectric, Al2O3 and fluorine plasma films were deposited between the CMT surface and a metal.
The properties of Schottky-barrier photodiodes based on CdxHg1-xTe with tunnel transparent dielectric
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The results are presented on the basis of characteristics of p-type CdHgTe (CMT) diodes with metal-tunnel transparent dielectric - semiconductor (MTTD photodiodes) in the 8-11 μm spectral range.
High-speed photodetectors and photodetective assemblies for receiving laser radiation in 0.3- to 11-um spectral range
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xResults of studying photodetectors (FD) and photodetecting assemblies (PDA) provided for receiving lased radiation in 0.2÷12 μm range are given in the paper. A possibility of using low-frequency CdxHg1-xTe photoresistors for recording CO2-laser pulses of up to 20 ns duration is discussed.
Isolating surface and bulk contributions in an HgCdTe junction diode
Vishnu Gopal,
Sudha Gupta,
R. K. Bhan,
et al.
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This paper reports the possibility of assessing the relative surface and bulk contributions in HgCdTe junction diodes by analyzing the Current - voltage (I - V) and dynamic impedance - voltage (Rd - V) characteristics of an individual diode. As an example, an analysis of the experimental data obtained on diodes fabricated in our laboratory on bulk grown p-type HgCdTe wafers using B+ implantation and ZnS passivating layers will be presented.
Simple computer model of an IR-photoconductor
L. I. Diakonov,
E. V. Susov,
Galina V. Chekanova
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The one-dimensional model of an IR photoconductor (PC) is developed for computer simulation. PC made from Hg1-xCdxTe (MCT) consists of the contact section 1, the active IR irradiated section 2 and the contact section 3. One can change the length of every section, its composition, the density of majority carriers in it and the recombination velocities of minority carriers at both contacts. The model allows to find the distribution of minority carriers on PC length and the dependence of voltage responsivity on electric field, applied to PC.
Heterostructures based on In-Ga-Al-N alloy system as promising media for photoelectronics and integrated optoelectronics
Oleg N. Ermakov,
Valery N. Martynov,
Galina A. Alexandrova,
et al.
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With account of the integrated optoelectronics global trends including intensive search of new monocrystalline, polycrystalline amorphous and polymer media review is presented for the present state and development trends of light emitters (light emitting diodes (LED’s), laser diodes (LD’s)) and photodetectors based on heterostructures in In - Ga - N alloy system. It’s shown that in accordance with theoretical calculation MOCVD-grown heterostructures based on In - Ga - N alloy system can be used for the photodetectors fabrication with photocurrent gain up to 106 as well as for high-efficiency LED’s (with luminous intensity more than 1 cd and short wavelength LD’s fabrication needed for optical storage system. Advantages and drawbacks of these devices are analyzed. Experimental data are presented on the electroluminescent and photoelectric characteristics of devices based on In-Ga-Al-N system. It’s supposed that statistical disorder in allay system leads to general broadening of luminescence and photosensitive spectra as well as to the smearing of optical nonlinearities that should be observed in quantum-confined system. In it’s turn it’s shown that statistical disorder manifestation can be related to peculiarities of MOCVD synthesis due to lattice mismatched growth and sharp nonlinear composition dependence on gaseous medium composition.
Performance of thermoelectrically cooled MCT photoconductors
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Wide nomenclature of Photoconductive Mercury-Cadmium Telluride / Hg1-xCdxTe (PC MCT) infrared radiation detectors with three-stage thermoelectric cooler (TEC) has been developed and fabricated. Performance of PC MCT infrared detectors are presented evidencing excellent peak detectivity D*(λp) and peak responsivity RV(λp) values in spectral ranges from 3,0 to 5,5 μm and from 7,5 to 10,6 μm.
Variations of MCT photoconductor performance with background flux density
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Variations of peak detectivity D*(λp) and peak responsivity RV(λp) values with background flux density have been examined on Photoconductive Mercury-Cadmium Telluride / Hg1-xCdxTe (PC MCT) infrared radiation detectors. Measurements were performed at operating temperature Top ≈ 78 K. Performance was measured on multi-element PC MCT infrared radiation detectors (N = 3x32 and 128 elements) with responsivity peak wavelength λp from 10,5 to 12,0 μm at the integral background flux density varied from (8-10)E+17 to (6-8)E+15 photon•cm-2•sec-1. Tested PC MCT infrared radiation detectors demonstrate background limited performance (BLIP).
Night Vision Systems
Image merging device
I. V. Borisova,
V. N. Gorenok,
A. N. Oparin,
et al.
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The developed image merging device executes joint processing of the multispectral information, transformation it into the integrated image, and representation on general visual display. In order to implement this device, the method of the image compilation is used that is based on the analysis and combination of the Fourier spectrum of the image vicinities. This method can be applied for compilation of any number of images and does not depend on their spectral range. In particular, compilation of the TV-images and IR-images is realized.
Simulators of dynamic thermal fields for thermal imaging systems bench test
Valeri Stefanov,
Vitaly Kravtchenko
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No abstract available.
Transient electronic processes in MIS-photo targets of vidicons sensitive to midband infrared radiation
A. V. Boroshnev,
N. Ph. Kovtonyuk
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No abstract available.
Utmost sensitivity of methods of visualization of zones of the increased concentration impurity of gases and vapors in the air with the help of thermal imagers and image intensifiers
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The method of remote detection (MRD) of zones of increased concentration ('clouds') of impurity gases and vapors in the air is based on absorption by these gases of ultra-violet (UV) radiation or infrared (IR) radiation of the scene (topographical targets, i.e. any objects in the field of vision of the device including the Earth surface, the sky, etc.). The method is recording of the images of the scene in very narrow spectral ranges coinciding witch spectral bands of absorption of these impurities. MRD can be realized with the help of two types of devices: 1. Devices on the basis of thermal imagers, recording impurity absorption on vibrational-rotationel transitions in the infrared (IR) spectral region. 2. Devices on the basis of electron-optical image intensifiers (II) recording impurity absorption on electron - vibrational transitions in the ultra-violet (UV) spectral region. In the report the calculations of utmost sensitivity capabilities MRD with reference to each of devices, implementing it are carried.
Analysis of utmost capabilities of detection of objects with the help of an observation thermal imager
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A mathematical model of an ideal observing thermal imager is developed. It was supposed at designing a model that: -the main noise source is a shot noise of photons irradiating photosensitive element (PSE); -temperatures and reflection factors of observed objects differ a little from corresponding scene characteristics; -image light brightness of i -th local object area on the indicator screen of the thermal imager (useful signal) is determined by the difference between on electric charge accumulated in PSE channel optically conjugated with this local area an electric charge accumulated in PSE channel optically conjugated with the scene. It is shown that detection possibility of i -th local object area on the thermal imager screen is determined unequivocally by its numerical index γi [equation] were Rep - the scene factor, t and r, correspondingly, are relations of temperatures and reflection factors of i-th local area and the scene. Calculations are carried of utmost signal / noise relations (for two spectral ranges used in thermal imaging : 3 - 5 μm and 8-14 μm) taking into account counterradiation, angular sizes of objects, characteristics of objects and the scene.
Calculation of utmost parameters of active vision system based on nonscanning thermal imager
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An active vision system (AVS) based on a non scanning thermal imager (TI) and CO2 - quantum amplifier of the image is offered. AVS mathematical model within which investigation of utmost signal / noise values and other system parameters depending on the distances to the scene - the area of observation (AO), an illumination impulse energy (W), an amplification factor (K) of a quantum amplifier, objective lens characteristics, spectral band width of a cooled filter of the thermal imager as well as object and scene characteristics is developed. Calculations were carried out for the following possible operating modes of a discussed vision system: - an active mode of a thermal imager with a cooled wideband filter; an active mode of a thermal imager with a cooled narrowband filter; - passive mode (W = 0, K = 1) of a thermal imager with a cooled wideband filter. As a result of carried out researches the opportunity and expediency of designing AVS, having a nonscanning thermal imager, impulse CO2 - quantum image amplifier and impulse CO2 - illumination laser are shown. It is shown that AVS have advantages over thermal imaging at observation of objects, temperature and reflection factors of which differ slightly from similar parameters of the scene. AVS depending on the W-K product can detect at a distance of up to 3000..5000m practically any local changes (you are interested in ) of a reflection factor. AVS not replacing the thermal imaging allow to receive additional information about observation objects. The images obtained with the help of AVS are more natural and more easy identified than thermal images received at the expense of the object own radiation. For quantitative determination of utmost values of AVS sensitivity it is offered to introduce a new parameter - NERD - 'radiation nose equivalent reflection factors difference'. IR active vision systems of vision, as well as a human vision and vision systems in the near IR - range on the basis image intensifiers provide obtaining the scene image having been irradiated with a source of illumination only at the expense of local differences in reflective properties. Such images are more natural and more easy identified than thermal images obtained at the expense of the scene own radiation.
Calculation of thermal contrasts and potentials of the infrared images in spectral ranges 3-5 um and 8-14 um at the availability and in the absence of counterradiation of the environment
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The calculations (for two spectral ranges, used in thermal imagines: 3...5 μm and 8...14 μm of thermal contrasts and potentials of the infrared images of objects of observation (OO), were carried out both availability the counterradiation of the environment, and in the absence of the counterradiation. (The counterradiation is a radiation, falling on OO, from the sky, from the surface of the Earth and from surface of the Earth surface). Is shown that in the infrared image in viewed spectral ranges (unlike the images of these OO in a visual spectral range) always (both at availability of and in its absence the counterradiation disappearance of some local areas (LA) - OO areas which temperature or (and) numerical coefficient γi the quantity of which is determined by is temperature, reflection factor and average for OO values of these quantities. The calculations of numerical quantities of coefficients of disappearing LA on the temperature of the environment were carried out. It is shown that the availability of a counterradiation alongside with the decrease diminution of the image contrast can (under certain conditions) result in inversion, i.e. that LA with smaller coefficients of radiation acquire more brightness, than LA with larger coefficients of radiation.
Laser-and-holographic measuring complex of FSPC GIPO
Vladimir P. Ivanov,
Anatoliy V. Lukin,
Andrey N. Melnikov
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The purpose, composition and technical features of the Laser-and-Holographic Measuring Complex of FSPC “GIPO” are considered. The methods for measuring optical parameters of objectives performed by using this complex are described. As an example, the results of the measurements of optical parameters of aspheric-and-diffractional objective “Kinar” are given. The objective “Kinar” possesses two fields of view, 3° and 9°, with focal lengths of 204 mm and 68 mm, respectively; the diameter of its active area is 100 mm, the relative aperture is 1:2.
A 1- to 11-um optical code sensor with Gray code system
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x1÷11 μm optical code sensor with Gray Code system based on miniaturized Photoconductive Mercury-Cadmium Telluride / Hg1-xCdxTe (PC MCT) detector with three-stage thermoelectric cooler (TEC) has been developed and fabricated. Performance of PC MCT detector is presented evidencing good detectivity D* and responsivity RV values in spectral range from, 1,0 to 10,6μm. Sensitive area structure allows producing of four digits Gray Code. Sensor can be used in electro-optical systems for spatial recognition of powerful sources of coherent infrared radiation.
Photoelectric Phenomena in Photodetectors
Photocapacitance effect in narrow bandgap PbSnTe
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Low frequency permittivity of PbSnTe(In) solid solution was investigated in darkness and under illumination. ε=2,000-300,000 was found depending on temperature and illumination. For the first time the increase of ε under illumination by about two orders was observed at LH temperature. Far IR cut off of the effect was estimated. It was found that the best correlation of calculations with experimental data took place if we supposed the presence of narrow band of PbSnTe In sensitivity within 300-400 μm spectral region.
Reverse currents of double-layer heterojunction diodes in conditions of Shockley-Read and Auger carrier generation
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The paper theoretically investigates the possibility of formation of negative differential resistance (NDR) region on the current-voltage characteristic (CVC) reverse branch of a diode with double layer heterojunction (DLHJ) in the diode’s base. The NDR formation is caused by decreasing the carrier thermal generation in the narrow gap part of the base with the thickness of the order of the Debye screening length at increase of the reverse bias. It is shown that the most favourable conditions for manifestation of the NDR are realized in the case when the carrier lifetime in the base region is determined by the Auger processes.
Effect of photo-induced space charge on dependence of intrinsic threshold photoresistor amplification on two-level recombination impurity concentration
Vyacheslav A. Kholodnov,
Pavel S. Serebrennikov
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Beyond the range of standard quasi-neutrality approximation dependence of photoelectric gain coefficient G on two-level recombination centers concentration N and applied electric field strength E0 is studied. Model: inter-band homogeneous absorption of weak radiation, acceptor type of recombination centers, extracting current contacts. The physical interpretation of the results obtained is given.
Near-contact vary-band layers as a means of suppressing the saturation of amplification in threshold CdHgTe photoconductive devices (photoresistors)
Vyacheslav A. Kholodnov,
Albina A. Drugova
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It is demonstrated in theory that saturation of the photoelectric gain G with increasing voltage V across a sample can be suppressed by introducing a vary-band layer near a current contact toward which the minority charge carries are pulled by the electric field. Inter-band mechanisms of photo-generation and recombination of non-equilibrium carriers are supposed. This is realized, for instance, in CdHeTe-based materials widely used for detecting weak optical radiation in the wavelength intervals of λ=8-12μm and λ=3-5μm.
Photosensitivity of heterostructure S1-xGex/Si taking into account free-carrier absorption of radiation and length of hot carrier energy path
Pavel S. Serebrennikov
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With allowance for a diffusion motion of hot carriers after absorption IR radiation by the method of Green function a calculation of quantum efficiency and photosensitivity is carried out. The dependence of quantum efficiency and photosensitivity on thickness of the Si1-xGex layer, free-carrier absorption coefficient of IR radiation and inelastic mean free path of hot carriers is obtained both for forward and backside (through a substrate) illumination.
On the degree to which the increase in the concentration of the recombination centers raises the efficiency of interband photoexcitation of carriers under weak optical radiation
Vyacheslav A. Kholodnov,
Albina A. Drugova
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The results of consistent (beyond the commonly used approximation of quasi-neutrality) theoretical analysis of the efficiency of inter-band photoexcitation of carriers in the case of absorption of weak optical radiation and non-equilibrium carrier recombination via deep impurity are presented. The model of a single recombination deep acceptor level and shallow donor impurity is considered. It is shown that the carrier photoexcitation efficiency can be drasticly increased at the cost of increase in the concentration of recombination centers. Also it is shown that the solution beyond approximation of quasi-neutrality may be basically differed from the quasi-neutral solutions.
Sensitization of IR photosensitivity by electrical field in indium selenide layered crystals
A. Sh. Abdinov,
R. F. Babayeva,
N. A. Ragimova,
et al.
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The early studies have demonstrated, that the laminated crystals of the indium selenide (InSe) are highly sensitive photoconductors in a wide range of temperature and light wavelength (formula available in paper). In the present report we have studied opportunities of expansion of a spectral range (sensitization) of the IR-photosensitivity of these crystals to the longer wavelengths. It is established, that in the high-resistance InSe samples with good injecting contacts in superlinear section of the CVC (where the appreciable injection takes place) at rather low temperatures (T less than or equal to 150K) a considerable photosensitivity occurs and in impurity area (up to 3.50 μm with a maximum at λ=2.64 μm a sensitization of the IR-photosensitivity for the investigated InSe single crystals by an electric field takes place. The dependence of this phenomenon on magnitude of the external electric field voltage, applied to the sample, as well as on the used contact materials, temperature, wavelength and intensity of an impurity light have been studied. Is has shown, that a sensitization of the IR-photosensitivity of the InSe single crystals by an electric field and the particular features of this phenomenon are conditioned with the presence of trapping levels of a various type and large-scale dimensional discontinuities. The values of fundamental parameters of trapping levels, as well as discontinuities have been estimated.
Negative infrared photoconductivity in CdS1-xSex films
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The negative infrared photoconductivity (NPH) has been observed for the first time in CdS1-xSex films, in the wavelength region of 0.700 ÷ 1.23 μm. at values of stimulating light intensity Φ = 100 ÷ 400 Lk. electrical field E = 0.5 ÷ 130 V/cm and temperature T = 265 ÷ 310 Κ. It is established, that basic laws of NPH explains on the basis of two-barrier model and in the considered conditions a charge carriers, overcome a barrier by tunneling. A films of CdS1-xSex can be used in IR engineering and negatronics.
Problems in the Technology of Photoelectronic Materials and Structures
Peculiarities of diffusion p-n junction formation in CdxHd1-xTe graded-bandgap epitaxial structures
A. P. Vlasov,
V. K. Pysarevsky,
A. V. Shevchenko,
et al.
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Investigations of graded-band-gap photosensitive epitaxial structures based on CdxHg1-xTe of n-type doped by As have been carried out. The epitaxial layers of CdxHg1-xTe(x=0.19÷0.34) grown by evaporation - condensation - diffusion in isothermal conditions (ISOVPE) and CdxHg1-xTe monocrystals (x=0.2;0.3) were used a basic material. As ion implanted (E=100 keV; D=5•1014, 5•1015, 6•1015 cm-2) surface of the epitaxial CdxHg1-xTe layer or highly doped (NAs≈1018 cm-3) thin (d=2÷4 μm surface films obtained by RF sputtering in Hg glow discharge on the monocrystal CdxHg1-xTe whose composition slightly differed from the basic one were used as admixtures. The diffusion of impurity and its activation have been performed in Hg and Te vapour at T > 400°C. Immediately after the diffusion process the samples were exposed to the long-term low-temperature annealing in a flow of Hg saturated vapor for recovery of the initial state of a basic material with respect to native defects. The diffusion profiles of the As distribution were determined by the SIMS analysis. Measurements of the diode structure parameters were carried out by differential Hall effect and conductivity in magnetic fields B=0÷1.8 T1, differential thermo-emf as well as by the direct observation of the p-n transition by EBIC method at 77K. The obtained results exhibit a high electroactivity of As in the samples. A rather complicated shape of the impurity distribution in the ISOVPE epitaxial CdxHg1-xTe points to the multicomponent mechanism of the As diffusion. Spectral and current-voltage characteristics of the graded-band-gap structures, as well as the influence of internal electric field on the structure properties have been investigated. It has been proposed the various ways for improvement of the epitaxial graded-band-gap CdxHg1-xTe structures parameters.
The state of the art and prospects of CdxHg1-xTe molecular beam epitaxy
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Molecular beam epitaxy of MCT makes it possible to dissolve the problems of producing MCT heteroepitaxial structures with uniformity parameters on the large size alternative substrates for IR PD of existent and new generation and the growing of MCT layers on Si -substrates. The information about characteristics of geteroepitaxial structures on GaAs-substrates, a new generation equipment for controlled growing of MCT layers by MBE and technological conditions allowed to grow the epitaxial buffer CdTe layers on Si-substrates are represented in this work.
Polycrystalline layers of silicon-germanium alloy for uncooled IR bolometers
I. B. Chistokhin,
I. P. Michailovsky,
B. I. Fomin,
et al.
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Polycrystalline layers of Si1-xGex of varying germanium fraction, in situ doped with boron, were received by molecular-beam deposition on layers of the silicon oxide and silicon nitride at temperatures <500°C. The structural properties of the films were studied, the dependences of the resistivity on the temperature and the low-frequency noise were measured. It has been demonstrated that, the temperature coefficient of resistance (TCR) in poly SiGe deposited on different dielectric coverings amounts to (3-4)%/grad and depends on resistance and grain size.
A control device: a beam structure of charged particles
A. N. Kozlov,
V. D. Smolyaninov,
A. P. Eremin,
et al.
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For maintenance repeatability technological of ion processing, it is necessary to support density of ion current and distribution density of ion current by constants. For this purpose the control device of ion sources with a wide beam has been developed. In this work the device for exact reproduction structure of a beam negatively or positively charged particles, is described. Calculation mistakes of measurement currents for the given device are resulted.
Features of growth and photoconductivity of epitaxial films of the Pb1-xMnxTe(Ga) solid solutions
I. R. Nuriev,
S. S. Farzaliyev,
Kh. D. Djalilova,
et al.
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In the present work the features of growth and photoconductivity of epitaxial films of (formula available in paper) grown on substrates BaF2 (111, 100) by method of molecular beam condensation are investigated. Is established, that of film with perfect crystal structure (W1/2=80÷100), thickness 0,5 divided by 1 μm, obtained at speeds of condensation υK=5 divided by 10 Angstrom /s and TS = 400°C. Were have obtained high - resistance films n, p - types of conductivity and is shown, that they are photosensitive. At that the maximum in spectra of photoconductivity is displaced to shorter waves with growth of the contents of manganese in samples (x = 0,01 divided by 0,04), that is explained by increase of width of the forbidden band zone.
Deposition of carbonic films from plasma of arc discharge without a cathode spot
I. Gasanov,
I. Gurbanov
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PVD ways of synthesis of hydrogen-free diamond-like films with high speed of a deposition of particles are analyzed. The technique of obtaining of coatings by means of a vacuum - arc discharge and of a plasma-optical filter provide the highest characteristics of -C amorphous diamond. However, the given way of synthesis is unwieldy and requires considerable costs. The capability of creation of the reactor of carbonic plasma in discharge with electron-beam heating of the cathode is consider. The control of power, entered into the graphitic cathode, allows essentially to limit a dispersion of an evaporated material.
Mechanism for creation of the mercury diffusion source at type conductivity conversion in p-Hg1-xCdxTe under ion-beam milling
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An analysis of the relaxation process for cation defects in Hg1-xCdxTe that form in the thermal spike at ion-beam milling (IBM) taking into account the neutral mercury bi-vacancies has been performed. It has been enabled to define a correct expression for concentration of the interstitial mercury created at IBM in the mercury diffusion source that is a boundary condition for equations of the diffusion kinetics. Expressions for depth of the p-n conductivity type conversion in both vacancy-doped p-Hg1-xCdxTe and one doped with As, Sb were obtained. There was a good accord between computed dependence of the conversion depth on the ion dose for vacancy-doped Hg1-xCdxTe (x≈0.2) with available literature experimental data. This fact well confirm the model adequacy.
Epitaxial MnCdHgTe layers obtained by RF sputtering in mercury plasma
Volodymyr Kavych,
Maria Lozynska,
Leonid Mansurov
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Thin MnCdHgTe epitaxial layers (4-6 μm) have been obtained by RF sputtering with localization of the mercury glow discharge in quasi-closed volume. The peculiarities of their condensation of CdTe substrates have been studied. The influence of technological parameters on the structural and electrophysical properties of MnCdHgTe layers has been investigated. The MnCdHgTe layers were chemically homogeneous in the surface of 2.5×2.5 cm2 size. On the basis of the Hall measurements carried out in the magnetic field 0.1 T it has been shown that epitaxial MnCdHgTe layers obtained at the substrate temperatures in the region from 220 up to 250°C had p-type conductivity with the carrier concentration of about 1016-1017 cm-3 the anomalously high values of the hole mobility (up to 1500 cm/Vs) at 77 K.
Isoperiodical Pb1-xSnxTe(In)/PbTe1-ySey heterojunctions obtained in ultrahigh vacuum
Eldar Yu. Salaev,
I. R. Nuriev,
A. M. Nazarov,
et al.
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On super high-vacuum installation (≤3÷5•10-9 mm Hg), in quasi-equilibrium conditions by the method of “hot wall”, in a uniform work cycle, photosensitive izoperiodical heterojunctions (HJ) Pb1-xSnxTe(In)/PbTe1-ySey have been received. Polished plates (100) and quick-spalled sides of BaF2(111) served as substrates. HJ components represent the ideally coordinated pair for the epitaxy in the structural relation. Volt-amper and spectral characteristics of HJ have been registred. The direct branch of VAC at small displacements submits of the exponential law J=J0exp(eU/βκT). At 77 K the coefficient β changes in the interval 1,5÷2, that is characteristic for the generation-recombination mechanism of the current flow through the region of the spatial charge. Maximal photosensitivity is observed at λmax=11,6 micron.
Functionalities of Cd1-xZnxSe films deposited from a water solution in IR region of a spectrum
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In the present work the features of an impurity and induced impurity photoconductivities in IR region, and also anomalous photoconduction and photochemical reaction in Cd1-xZnxSe films are considered depending on film deposition and heat treatment (HT) modes. The formation of Cdi-Cdi, Zni-Zni, Vse-Zni etc. associations in Cd1-xZnxSe films, providing occurrence of optical active electronic states, carried in an interval of energy 0.3÷0.6 eV, allows to use of these films for creation non-cooled photodetectors of IR-range. At illumination of films by λ=0.95 μm light, the anomalous photoconductivity and photomemory phenomenon were observed, connected with defects of metastable states, which concentration can be controlled by film structure, deposition and HT modes, and limits by tunnel transitions of no basic located electrons and holes between r- and s-centres. The photochemical reaction with activation energy of 0.17÷0.21 eV, was observed at illumination (by λ=1.25 μm light) of Cd0.8Zn0.2Se films heart treated on air during 10÷15 minutes. It represents a disintegration process of donor-acceptor pairs, consisting r-centres and Cdi, Zni donors, and caused by precipitation conditions and HT.
Electron diffraction study of photosensitive heterostructures PbSnTe-PbTe grown by MBE
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Electron diffraction study of PbTe and PbSnTe epitaxial layer surface and heterojunctions on their bases grown by MBE on mica was carried out. The aim of this study was determination of correlation between diffusion streaks intensity on diffraction patterns and photoelectric parameters of p-n junctions made in these structures. The diffusion streaks intensity depends on thickness and temperature of layers growing. More pronounced streaks on electron diffraction patterns are observed from thicker layers (d>1 μm) grown at higher temperatures (>300°C). Diffusion streaks intensity of heterolayers PbSnTe-PbTe grown at 380-400°C changes most heavily at changing film thickness from tenth fractions of micron till approx. 1 μm. At further increase of film thickness till approx. 4-5 μm diffusion streaks intensity changes slightly. Peak of heterojunction of Pb1-xSnxTe-PbTe (x=0.2) photosensitivity grown at 380-400°C at film thickness 0.5-1μm locates at 4.5μm with sloping decreasing till 6μm. Heterojunction with same composition grown at same temperature with film thickness 4-5μm has peak of photoresponsivity at 8.5 μm. The correlation between diffusion streaks intensity and photoelectric parameters of film p-n structures is found out.
Requirements for Photodetectors and their characteristics Measuring
Low-frequency noise spectra of high-quality MCT photoconductors
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Low-frequency flicker-noise “1/f” spectra were examined on Photoconductive Mercury-Cadmium Telluride / Hg1-xCdxTe (PC MCT) infrared radiation detectors. Noise measurements were performed on PC MCT detectors with responsivity peak wavelength λp from 3,0 to 5,5 μm and from 10,5 to 12,0 μm at operating temperature Top ≈ 205 - 210 K and ≈ 78 K respectively. Tested high quality PC MCT infrared radiation detectors show extremely low spectral density of excess “1/f” noise and low values of noise-knee frequency from 10 to 150 Hz and demonstrate high-level performance.
Improvement of optical method of oxygen-in-silicon characterization and design consideration in measuring setup for detailed nondestructive mapping of interstitial oxygen
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Under the today’s tendency of progressive growth of integration level and diminishing of the basic element size of microelectronic devices, the significance of control of spatial distribution of defect-inducing impurities during device processing treatments increases. One of the most important impurities for silicon microelectronics is oxygen, which already presents in the initial Czochralski-grown silicon. Existing standard optical methods of measuring interstitial O-in-Si content based on analysis of silicon wafer’s transmission spectra on the IR optical band of ~ 9 μm doesn’t provide the desired degree of spatial resolution. The purpose of this work is to modify measuring method in such a way to make it possible for one to obtain, in relatively fast manner, oxygen distribution “map” over the wafer’s area, with spatial resolution up to 30..50 μm. The work describes the approach to measuring setup construction, which provides oxygen distribution control in silicon wafers containing O in concentration lying between 1017...3*1018 cm3 with the accuracy of 5% and with the above localization degree. Different realizations of the optical source, projection optics, detector and signal processing system are discussed, and the best choice is grounded. Presented are the technical estimations showing the evidence for the measuring setup to provide the desired features when tunable laser diode is used as a light source along with the special parabolic collimator, cylindrical projection optics and commercially available time-delay-and-integration CMT LWIR detectors.
Influence of ionizing irradiation on photoelectric properties of GaSxSe1-x solid solutions
K. A. Askerov,
F. I. Ismaylov
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The influence of ionizing irradiation of a various kind on photoelectric properties of the GaSxSe1-x (0≤x≤0.25) has been investigated. It is established that hte change of physical properties of researched samples as a result of the influence of the ionizing irradiation is convertible process connected, basically, with effects of ionization and surface effects. It is shown, that these materials can be used as a sensitive element for manufacturing gauges of the ionizing irradiation.
A comparative study and optimal choice of the method of determination of interstitial oxygen-in-silicon concentration from optical transmission spectra
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Currently, the commonly used method for determination of interstitial O-in-Si concentration, Nox, which is responsible for defect formation in very different types of semiconductor devices, is measuring optical transmission spectra of silicon wafers in the 8 to 11 μm band. The Nox value is extracted from the experimental data by use of standardized algorithms assuming quasi-continuous sequence of spectral transmission samples are available. According to USA standard (ASTM F951-96) such a procedure is assumed to be applied to the separate wafer’s area regions with the diameter of about 7 mm. However, the very much better spatial resolution (up to 30-50 μm is desired under the condition of progressive decreasing of basic element’s characteristic size. To do this, one cannot use the standard algorithms assuming quasi-continuous sequence of spectral samples being available in relatively wide (~3 μm spectral band, because of unrealistic times the measurements requires for. For to choose more economical algorithm of extracting the No value we have compared several proposed calculation methods, which are based upon moderate numbers of spectral samples. As the input test data set for the calculations, the series of experimental samples were taken with the step in wavelength of 0.05 μm obtained on the silicon wafers of different thickness (0.4-2 mm) and of various Nox. The results show that the algorithms using small number of samples (one or two), being optimized properly, do not yields to the standard time-consuming procedure.
Influence of ionizing radiation on efficiency of photodiodes on the basis of gallium telluride
K. A. Askerov,
F. K. Isayev,
D. I. Karayev,
et al.
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Influence of the nuclear explosion factors on basic parameters of photodiodes developed on the basis of layered gallium telluride crystals, operating in the spectral range 0.4 ÷ 1.1 μm has been studied. Results of study of the effect pulsing gamma-irradiation and pulsing neutron-irradiation show that photoreceivers on the basis of GaTe crystals is perspective for systems operating in visible and near IR-region.
Influence of penetrating radiation on the spectral characteristics of indium selenide doped by silver and germanium
K. A. Askerov,
A. Z. Abasova,
F. K. Isayev
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In present report the spectral and integrated photosensitivity before and after the influence of gamma-quanta in an interval of dozes 104-108 R and pulse neutrons of fluence 1012-1014 cm-2 on indium selenide single crystals doped by silver and germanium atoms have been investigated. The irradiation of InSe:Ag by gamma-quanta up to 105 R doze does not result in appreciable changes of photosensitivity of fundamental absorption and the sensitivity in short-wave region appreciably decreases. The further increase of the gamma-quanta doze up to 108 R changes photosensitivity only on 15-20%.
Influence of ionizing irradiation on the basis characteristics of cooled photoresistors on the basis CdxHg1-xTe
Eldar Y. Salaev,
D. Sh. Abdinov,
K. A. Askerov
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The influence of the ionizing irradiation of different kind on the basic parameters, elements, designs and constructional materials of photoreceivers on the basis of CdxHg1-xTe solid solution have been investigated. It is established, that the change of the basic parameters of the photoresistors is mainly connected with the change of properties of photosensitive elements. It has been shown that these photoreceivers may me used for operating under high irradiation conditions.
Physical Properties of Materials for Thermoelectric Coolers
Magnetothermoelectrical and adhesive properties of commutation contacts of thermoelements on the basis of extruded samples of Bi85Sb15 solid solution
M. M. Tagiyev
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A study of electrical and adhesive properties of transient contacts for extruded samples of Bi85Sb15 solid solutions have been conducted with alloys: 25Bi + 50Pb + 12.5Cd + 12.5Sn with Tm = 343 K (Wood"s alloy) and 57Bi + 45Sn with Tm =412 K in temperature range ~77-300 K and magnetic field intensity (H) up to ~74x104 A/m. It is shown that resistance of transient contacts (rk) of the extruded of Bi85Sb15 solid solution with the specified contact alloys at ~77K is determined by the resistance of the structure the solid solution Bi85Sb15-solid solution Bi85Sb15, heavily doped by Pb and Sn atoms, diffused from contact alloy into near-contact area of the Bi85Sb15 solid solution. It is established, that by doping extruded samples of Bi85Sb15 solid solution with Pb atoms it is possible to achieve reduction of a transient contact resistance rk in Bi85Sb15 solid solution - contact alloy interface.
Three-stage thermoelectrical module for ~200 K temperature level
T. D. Aliyeva,
N. M. Akhundova,
D. Sh. Abdinov
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It has been designed, manufactured and tested the three-stade thermoelectric module with the following basic parameters: at the environment temperature equal ~295Κ temperature of a heat-absorbing surface is ~200Κ, cold productivity ~100mW, power supply ~4,2 W, current supply ~2,0 A, operating ( mode reaching ) time~70s. The module exceeds in the basic parameters and profitability of the analogs.
The hybrid cooler on the basis of extruded samples Bi85Sb15 solid solutions
M. M. Tagiyev,
N. E. Gasanov,
G. D. Abdinova
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It has been developed hybrid cooler, consists of two blocks, and operating on the basis of Peltier and magneto-Peltier effects. The first block, operating on the basis of Peltier effects consists of four stage with 24 W power supply and 250 mW cold productivity, and second block - of one cascade of one thermoelement, operating on the basis of magneto-Peltier effects in a magnetic field (~0,3T). It hase been shown, that at use of the specified materials temperature of the heat-adsorbing surface of the hybrid cooler falls up to 150 Κ. Designed hybrid cooler with ~24,5 W power supply and 20 mW cold productivity can be applied to cooling elements with ~15-20 mW thermal loading.
Material on the basis of PbTe for p-branches of thermoelectric coolers
Z. F. Agayev,
E. A. Allahverdiyev,
G. M. Murtuzov,
et al.
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The results of the studying of thermo-e.m.f. (α), electrical conductivity (σ) and thermal conductivity χ coefficients for PbTe over the temperature range 80÷300 Κ have been presented. It is established that in non-annealed PbTe samples with the reduction of temperature change in the conductivity from electronic to hole type occurs at low temperatures. After annealing at this sample n-type conductivity is observed over all investigated temperature range.
Photodetectors with thermoelectric coolers for 3- to 5-um and 10- to 12-um spectral region
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It have been designed, manufactured and tested the photodetectors for a spectral region 3÷5 μm (IFE-1) and 10÷12μm (IFE-2) with a built-in thermoelectric coolers (TEC). The testing have shown, that the photodetectors are inconvertible against vibration in a frequency band from 10 up to 2500 Hz at acceleration up to 10 g, repeated shocks at a loading up to 15 g and duration of a shock impulse from 1 up to 5 μs (total number of shocks 12000), single chock at peak acceleration 100 g and pulse length 0,1-2 μs (total number of shocks -9). In addition carried out(spent) test on action of linear (longitudinal) acceleration up to 100 g at duration of action not less 10 s was carried on. After realization of tests any damages of a sensitive element and commutation systems, as well as all device as a whole were not observed.