Proceedings Volume 5065

Sixth International Conference on Material Science and Material Properties for Infrared Optoelectronics

Fiodor F. Sizov, Johanna V. Gumenjuk-Sichevska, Sergey A. Kostyukevych
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Proceedings Volume 5065

Sixth International Conference on Material Science and Material Properties for Infrared Optoelectronics

Fiodor F. Sizov, Johanna V. Gumenjuk-Sichevska, Sergey A. Kostyukevych
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 14 April 2003
Contents: 3 Sessions, 33 Papers, 0 Presentations
Conference: Sixth International Conference on Material Science and Material Properties for Infrared Optoelectronics 2002
Volume Number: 5065

Table of Contents

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Table of Contents

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  • Device Applications
  • Characterization and Properties
  • Growth Techniques and Technological Processing
Device Applications
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Computational optoelectromechanics and its application to MEMS VCSELs
Vertical-cavity surface-emitting lasers (VCSELs) have been research extensively as key components for next-generation of wireless communication, computing, processing, switching and optical devices. Conventional VCSELs integrate two oppositely doped distributed Bragg reflectors (DBR) with a cavity layer between them. In the center of the cavity layer there is an active region with multiple quantum wells. Current is injected into the active region using oxide or proton-implanted apertures. Recent research and developments have been progressed to the tunable, long-wavelength, and multiple-wavelength MEMS-based electrically- and optically-pumped VCSELs. These MEMS VCSELs integrate a bottom n-DBR (for example, GaAs-AlGaAs), a cavity layer with the active region (for example, InGaAS), and a top mirror. The top mirror integrates p-DBR (oxidation and sacrificial layers, AlAs, AlGaAs) -- air gap -- top n-DBR suspended above the laser cavity and controlled (displaced or bent) by the nano- or microscale actuators. The current is fed through the p-DBR. Hence, optoelectronics and microelectromechics are examined for MEMS VCSELs. In contrast, the optically-pumped VCSLEs with membrane MEMS integrate n-DBR, cavity layer with the active region, p-DBR, sacrificial layer (for example, AlGaAs) and top mirror (quarter-wave GaAs layer). Usually, the wavelength of tunable VCSELs can be varied within 10 - 30 nm increments. To optimize MEMS VCSELs, far-reaching research and developments must be carried out. Recently, novel MEMS VCSELs topologies and configurations have been devised. These MEMS VCSELs must be modeled, analyzed, and optimized. The computer-aided-design will lead to essential improvement of lasers optimizing their performance. High-fidelity modeling, heterogeneous simulation, data-intensive analysis and synergetic design of MEMS VCSELs are part of a newly emerging field of computational optoelectromechanics. In fact, high-fidelity modeling is an important part in synthesis and design of affordable high-performance MEMS VCSELs with the desired performance and reliability. The basic equations to model VCSELs are found using the quantum mechanics, quantum electromagnetic field theory, Maxwell's and Navier-Stokes equations. To derive the equations of motion for nano- or microactuators, the functional density concept is used to find the force, and Newtonian mechanics allows one to derive the differential equations to integrate mechanical dynamics. This paper focuses on the development of the theory of computational optoelectromechanics and its application to computer-aided design of MEMS VCSELs. The modeling, simulation, analysis and design results are reported and illustrated.
Spatially nanostructured silicon for optical applications
Dmitri I. Kovalev, Joachim Diener, Nicolai Kuenzner, et al.
We report on a strong intrinsic optical anisotropy of silicon induced by its dielectric nanopatterning. As a result, an in-plane birefringence for nanostructured (110) Si surfaces is found to be 105 times stronger than that observed in bulk silicon crystals. A difference in the main values of the anisotropic refractive index exceeds that one of any natural birefringent crystals. The anisotropy parameters are found to be strongly dependent on the typical size of the silicon nanowires assembling the layers. The value of birefringence is dependent also on the dielectric surrounding of silicon nanoparticles assembling these layers. We show that stacks of layers having alternative refractive indices act as a distributed Bragg reflectors or optical microcavities. Dichroic reflection/transmission behavior of these structures sensitive to the polarization of the incident linearly polarized light is demonstrated. These findings open the possibility of an application of optical devices based on birefringent silicon layers in a wide spectral range.
Competition of infrared detector technologies
Performance limits of infrared photon and thermal detectors are presented. Due to fundamental different types of noise, these two classes of detectors have different dependencies of detectivities on wavelength and temperature. Special attention is put on competition of QWIPs and HgCdTe photodiodes in long wavelength infrared spectral region. Final part of the paper is devoted to uncooled two-dimensional arrays of thermal detectors. Two most important detection mechanisms, namely, resistive bolometer and pyroelectric detectors are considered. The development of outstanding technical achievements in uncooled thermal imaging is also presented.
IR photodetectors based on MBE-grown MCT layers
A complete technological cycle has been designed to produce photodetector arrays, which involves MBE growth of Hg1-xCdxTe (MCT) heteroepitaxial layers, fabrication of MCT-based photodetector structures, manufacture of silicon array multiplexers and hybrid assembly of a photodetector module consisting of a photodetector and multiplexer by means of indium micro bumps. Photoelectric parameters are given of photodetector array modules on the basis of photodiodes for the middle (3 - 3.5 μm) and far (8 - 12 μm) infrared ranges, operating at 78 - 80 K and 200 - 220 K temperatures.
One-dimensional photonic crystal as a many-positional adder functioning on closed electromagnetic modes
Eugene Ya. Glushko, Svetlana L. Legusha
The system of one-dimensional photonic crystals combined with fiber waveguides, splitters and amplifiers is proposed as an optical binary signal's adder. We consider two or more angle distributed many-positional external binary signals hitting into the photonic crystal through the fiber entrances. Such kind of entrance construction due to spherical end of fiber allows external illumination to penetrate directly inside the range of total intrinsic reflection and populate photonic eigenmodes. Each component of complex signal hits into the 1D crystal at a fixed angle corresponding to mode angle at given frequency. The output sum signal is distributed onto the same fibers' angles. Physical principles and parameters of sub-picosecond infrared fiber-photonic processor are discussed.
IRFPA real-time nonuniformity correction using the FPGA technology
Lingbin Kong, Xinjian Yi, Dianhong Wang, et al.
The infrared focal plane array (IRFPA) imaging system is the trend of IR imaging technology. However the most difficult problem associated with the IRFPA is intrinsic spatial photo-response nonuniformity. Practicable and real-time nonuniformity correction (NUC) is a key technology in the application of IRFPA. The main specifications and parameters of IRFPA nonuniformity are researched, and a real-time new nonuniformity correction method by using the field programmable gate array (FPGA) technology is presented in this paper. It has the advantage of large dynamic range, small storage capacity, high processing speed and high corrective accuracy, etc. Then the correction principle and main steps are described in detail. The block diagram of hardware circuit and the working processes were introduced. The experimental results are satisfactory, showing advantage of this method.
Multifunctional controlled IR-emitting element
Konstantin Yu. Guga, Alexej G. Kollyukh, Anatoli I. Liptuga, et al.
Results of investigations of the multifunctional emitting element based on a p+-p-p+ Ge structure with anisotropic conductivity induced by magnetic field are presented. It was shown that the presence of complex controlled concentration profiles in the element essentially widens functional possibilities of the emitting element, which enables to model positive, negative or alternating contrast. This provides possibility to use it as a base in the specialized emitting sources intended for the calibration of infrared systems.
Model of control of glow discharge electron gun current for microelectronics production applications
S. V. Denbnovetsky, V. I. Melnyk, I. V. Melnyk, et al.
The problems of simulation of discharge current control and its gas-dynamic stabilization for technological glow discharge electron guns with a cold cathode are considered in a paper. Such guns are successfully operated in soft vacuum and can be used in modern microelectronic technologies for providing of thermal operations with using different technological gases including active ones. The results of theoretical and experimental investigation of automatic control system of current of electron gun which were used for deposition of coatings in reactive gas medium are presented in article. Time of regulation for considered system did not exceed 400 ms. Is proved, that the automatic control of a current of a glow discharge electron gun by pressure variation its volume is effective on all operation range of pressure, and the minimum time of a current regulation can be tens -- hundred of ms, and this fact is allow to use in the majority of technological operations for microelectronic production.
Features of thermal radiation of semitransparent objects
Alexej G. Kollyukh, Anatoli J. Liptuga, Vasiliy A. Morozhenko, et al.
Based on the analysis of absorptances of plane-parallel objects, distinctive features of their thermal radiation caused by multi-beam interference are investigated. Using a semiconductor as an example, thermal radiation spectra for plane-parallel and identical non-plane-parallel plates in the spectral region beyond the fundamental absorption edge are calculated, and a comparison of the parameters of these spectra was carried out. It is shown that, in spectral regions corresponding to interference maxima, the radiant emittance of a plane-parallel plate can exceed many times over that of non-plane-parallel plate. For very small values of the absorption coefficient of a plane-parallel plate, its radiant emittance can attain the value of 0.5 of that of a blackbody in these spectral regions. It is proved that the results obtained can be used for creation of new controllable thermal radiation sources.
Characterization and Properties
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Photogalvanic currents in quantum well structures induced by infrared radiation
Sergey D. Ganichev
A circular photogalvanic effect and a magnetic field induced circular photogalvanic effects caused by absorption of far infrared radiation have been observed in quantum well (QW) structures. Applying circularly polarized infrared radiation a monopolar spin polarization has been achieved. The spin polarization results in a directed motion of free carriers in the plane of a quantum well. The coupling of the helicity of the incoming photons to spin polarized final states with net momentum is caused by angular momentum selection rules together with band splitting in k-space due to k-linear terms in the Hamiltonian. These spin photocurrents have been observed in GaAs, InAs, and Si/Ge QW structures for a wide temperature range from room to liquid helium temperature by using a pulsed far-infrard molecular laser delivering 100 ns pulses at wavelengths from 9 μm to 280 μm. The conversion of spin orientation of carriers into directed motion provides efficient methods to determine spin relaxation times of electrons in n-type materials and of holes in p-type materials.
Electromagnetic field structure and quenching in one-dimensional photonic crystals
Eugene Ya. Glushko, Svetlana L. Legusha, Anvar A. Zakhidov
The study is devoted to closed and transferred electromagnetic field in one-dimensional both transparent photonic crystals and crystals containing layers which absorb irradiation alternated by transparent layers. General theory of irrdiation closed inside the crystal is developed both in case transparent and adsorbing metallic photonic crystals in wide frequency range. True or absolute photonic gaps existing in the total reflection angle range are analyzed on the base of internal problem's analytical solution for 1D layered superlattices. We have investigated the frequency-angle diagrams for TM and TE photonic spectra trapped inside the whole reflection range for mesoscopic and macroscopic hierarchical 1D photonic crystals of varied topologies, geometry and materials. The effects of double refraction in binary multi-layered system and photon localization in finite periodic layered structures are investigated analytically and numerically. Energy storage and energy decay time in photonic crystals are considered with account for field amplitudes distribution inside the structure and angular band kinetics. The effect of sharp focusing of the butt-end emission for closed electromagnetic waves in 1D photonic crystals is discussed.
Quartz as artificial pyroactive material
V. F. Kosorotov, Ivan V. Blonsky, Ludmila V. Shchedrina, et al.
Thermodynamics, physical nature and production mechanisms of polar states initiated by external nonscalar action in noncentral crystals are investigated. Spatially inhomogeneous heating of nonpolar piezoelectric crystals provides the means of producing new properties in crystals which do not exhibit these properties in the thermodynamically equilibrium state, creating artificial pyroactive media with controlled physical parameters. Theoretical and experimental explorations are aimed at the investigation of tertiary pyroelectric effect that has indicated potential for a solving problems of monitoring and registering intense laser radiation. A novel approach to the development of infrared pyroelectric sensors and devices on the basis of the proposed artificial pyroactive materials is formulated. Crystal quartz showing pyroactive properties under spatially inhomogeneous heating conditions is suggested as sensitive element for pyroelectric transmission type power sensors in visible and near IR-range of spectrum.
Nonelastic electron scattering in HgTe
O. P. Malyk
By exact solution of stationary Boltzmann equation the nonequilibrium charge carrier distribution function is obtained. In the temperature range 4.2 - 300 K the main electron scattering mechanism are considered taking into account the nonelastic electron interaction with optical vibrations of the crystal lattice.
Substrate influence on infrared absorption by clusters of small spheres
Victor V. Gozhenko, Leonid G. Grechko, N. G. Shkoda, et al.
In this work we study the effects of a semi-infinite substrate on the electromagnetic properties of a cluster of small spheres in the electrostatic approximation. General expressions for coefficients of the multipole expansion of the electrostatic potential of a sphere accounting for interaction between ambient particles and the substrate are obtained. Expressions for the polarizability tensor and resonant frequencies of a single sphere above a substrate are derived for the case of Lorentzian permittivities of both the sphere and substrate. Optical properties of small spheres are shown to be anisotropic due to the substrate influence.
Threshold characteristics of p-Si-PtSi barriers with highly-doped surface nanolayer
Platinum silicide Schottky barrier detectors are widely used for application in the medium infrared wavelength region. The increase of cutoff wavelength and responsivity of PtSi-Si photodevices is possible by formation of highly-doped thin layer near to the semiconductor surface. We propose for this aim to form highly-doped nanolayer in p-Si by recoil implantation of boron. It is experimental established that profile of impirity distribution in surface layer is exponential. The doping concentration at the silicide/silicon interface is 1018 - 1020 cm-3 and thickness of surface layer is 8 - 12 nm. We have calculated the spectral, threshold, and noise characteristics of p-Si-PtSi photodetectors with highly-doped surface layers produced by molecular-beam epitaxy and short-pulse dopant implantation by a recoil method.
Influence of doping methods on electro-physical properties of CdTe:Mn crystals
E. S. Nikonyuk, Z. I. Zakharuk, Ilary M. Rarenko, et al.
Electro-physical properties of CdTe:Mn crystals depending on doping method were studied. Three doping schemes were used: I - Mn was introduced to the melt of stoichiometric CdTe; II -- Cd, Mn and Te components were loaded according to the Cd1-xMnxTe solid solution; III -- Mn was introduced with loaded in stoichiometric proportions Cd and Te components. It was found that the properties of CdTe:Mn essentially depend on the method of impurity introduction. It may be caused by the difference of Mn atom position in CdTe lattice in different doping schemes and by the interaction of manganese atom with cadmium vacancy. For Cd1-xMnxTe (x = 0,02-0,30) solid solution crystals obtained according to scheme III a hysteresis type relaxation is observed in "heating-cooling" circles like that in p-CdTe crystals doped by Cu and Ag impurities.
IR photodetectors on CdSb, In4Se3, In4Te3-epitaxial barrier structures
B. M. Gritsyuk, O. V. Galochkin, A. I. Rarenko, et al.
Perfect homo- and heteroepitaxial structures of n- and p-type conductivity on CdSb, In4Se3, In4Te3 semiconductors and their solid solutions were grown. On formed p-n-junctions there were investigated spectral dependence of photo-emf and detectivity in λ = 1 - 3 μm interval. It is shown the possibility of their using as IR-photodetectors.
Electrical properties of HgMnTe Schottky diodes
Leonid A. Kosyachenko, Sergey E. Ostapov, Andrey V. Markov, et al.
The electrical properties of Al-Hg1-xMnxTe (x = 0.08 - 0.1) Schottky barriers are investigated. The main parameters of the diode structure and charge transport mechanisms responsible for their characteristics, tunneling and over-barrier passage of carriers, are determined. The features of the diode electrical characteristics caused by the narrow bandgap and big difference between effective masses of carriers are revealed. The results obtained experimentally and theoretically testify of the high detectivity of the diodes studied.
Study of HgCdMnZnTe main-band parameters
Sergey E. Ostapov
With the k-p method have been calculated the main band parameters of HgCdMnZnTe, such as energy gap, intrinsic carrier concentration, electron effective mass and carrier lifetime.
Electrical and optical properties of indium antimonide doped by cadmium and tellurium
Alexander V. Brodovoi, P. V. Pleskatch, S. G. Bunchuk, et al.
In the present work indium antimonide crystals doped by cadmium and tellurium in equiatomic quantities have been studied. It was shown that (InSb)1-x(CdTe)x solid solutions with the mole concentration x ≤ 0.05 arises. Two maxima at x = 0.0025 and x = 0.02 - 0.03 and a minimum at x = 0.01 were found out in the dependence of the lattice constant on the composition x. It is shown that the change in the energy gap ΔE is proportional to the change in the lattice constant Δa. Dependencies of the effective electron mass, the electron density and the mobility on the composition x and temperature were studied. Minimal values of the effective electron mass and the energy gap were observed in the composition range x = 0.02 - 0.03 and were as follows meff = 0.009 mo and Eg = 0.07 eV (mo is the free electron mass). Anomalous (as large as tenfold) increase of diamagnetism was found out in the temperature dependence of the magnetic susceptibility of the solid solution with x = 0.05 in the range 4.2 K < T < 30 K.
Interplay of phase transformation temperatures and Dingle temperatures in narrow-gap semiconductors
Alexander I. Dmitriev, M. V. Radchenko, George V. Lashkarev, et al.
The results of neutron diffraction researches in the temperature region 10 - 290 K as well as thermoelectric, magnetic and electric properties of solid solution Pb0,8Sn0,2Te of high structural perfection within temperature range (4,2-25) K in magnetic fields up to 4T are represented. The analysis of experimental data testifies to the existence of phase transformations at Tc1 = (35 ± 5) K, Tc2 = (110 ± 5) K, Tc3 = (140 ± 5) K and Tc4 = (260 ± 5) K. The temperature hysterenis of thermoelectric power is observed in the interval Tc1 < T < Tc2. It testifies to the ferroelectrics transition of I kind and lowering of crystal symmetry. Phase transformations at Tc3 and Tc4 are transitions of presumable the II kind. The structural perfection improvement of single crystals Pb0,8Sn0,2Te results in the shift of the first phase transition temperature Tc1 from 20 - 25 K to Tc1 = 35 K. This shift can be described by Dingle temperature - TD, which is determine a degree of crystal imperfection at T = O K.
Electronic activity of dislocations and point defects of deformation origin in Hg1-xCdxTe
S. G. Gassan-Zade, G. A. Shepelskii, S. V. Staryi, et al.
The addition of comparatively low density of dislocations Ndis less than or equal to 107 cm-2 causes the essential quantitative, and qualitative changes of kinetic coefficients in Hg1-xCdxTe (MCT) crystals. In n-type crystals the electrons concentration increases dramatically, and the electrons mobility decreases. Moreover, the characteristic maxima appears in the electrons Hall coefficient RH and mobility temperature dependency, being an evidence of the existence of the carriers of two types. In p-type crystals we observed the increase of halls concentration and the change of sign of RH with temperature and magnetic field in the low temperature region (T equal to 4.2 divided by 40 K), together with a transition from activation conductivity to metallic one. It was demonstrated, that these changes are caused not by electronic states of the dislocation core directly, but by the point defects, formed in the process of dislocation movement, and concenrated in the gliding planes. The amount of experimental data can be explained within the idea of the formation of the channels of the different type of conductivity connected with dislocations net, in the matrix of the crystal. This net is formed by tubes of the volume space charge around the dislocation core, penetrating throughout the. The dislocation core itself is formed by the line of cations and anions respectively with the dangling bounds of crystalline lattice.
Influence of the electrochemical process of the macroporous silicon fabrication on surface local chemical states
Oleq O. Lytvynenko, Lyudmila A. Karachevtseva, Elza A. Malovichko, et al.
Local chemical states and structure of microporous layers on macropore walls were investigated before and after KOH etching using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy. Micropore layers of the thickness 100 - 700 nm were formed on macropore walls of two-dimensional silicon structures. Higher current densities gave the thinner microporous. FTIR spectroscopy results showed content strong peak 465 cm-1 attributed to SiO2 structures and Si-Si peak 650 cm-1 observed due to high porosity and big total surface of microporous layers. After KOH etching Si-O peak is presented in FTIR spectra of all investigated structures. Macroporous silicon structures fabricated at low initial bias U0 less of 1-st peak in I-V characteristic after KOH etching content mainly OH, Si-O and Si-Si peaks.
Growth Techniques and Technological Processing
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Prototype infrared optical sensor and solar cell made of B-FeSi2 thin film
Shinan Wang, Naotaka Otogawa, Yasuhiko Fukuzawa, et al.
A prototype infrared optical sensor has been fabricated by using a 0.21 μm-thick β-iron disilicide (β-FeSi2) thin film prepared by reactive deposition epitaxy (RDE) on an n-type (100) Si substrate (ρ approximately 1.5 Ωcm). Manganese ions (Mn+) were implanted into the β-FeSi2 thin film as p-type dopants with a total dose of 5.5 x 1018 cm-3. Al and AuSb thin films were metallized on β-FeSi2 and Si surfaces respectively as electrodes. A circle area of the FeSi2 film was left naked as the illumination window. The good diode characteristic confirmed the high quality of the pn junction. The spectroscopic spectrum indicated a clear photoresponse at room temperature. As evaluated by a standard solar simulator, the device provided an open-circuit voltage of voc = 261 mV and a short-circuit current density of Jsc = 3.1 mA/cm2, suggesting a large potential of such devices in solar energy conversion. Rutherford backscattering spectroscopy (RBS) measurements found a large volume of oxygen in the surface of the β-FeSi2 thin film and severe Fe/Si interdiffusion at the silicide-Si interface. These unwanted effects may be responsible for the unideal device performance. Methods to solve these problems are discussed including a proposal of an all-iron-silicide structure.
Photonic 2D crystals built from nanotubes, nanochannels, and nanowires: review of progress in synthesis, properties, and promising applications
Vladimir V. Pokropivny
Recent progress in a synthesis, properties and promising application of nanotube, nanowire 2D photonic crystals, nanochannel membranes and aligned nanotube arrays is shortly reviewed. Their novel applications for future nanoelectronics and micro-lasers are outlined. High-Tc 2D superconductor on base of MgB2, NbSe2 or other superconducting nanotubes with expected record Tc is substantiated. Extremely high-frequency electroacoustic hypersound transducer for tera-gertz range on base of BN-tube/SiC-nanofibers rope is suggested.
Defect structure and diffusion of defects in narrow-gap Hg1-xCdxTe crystals
V. V. Bogoboyashchyy
Formation and diffusion of native point defects mercury vacancies and interstitials in Hg1-xCdxTe crystals (x approximately 0.2...0.3) are investigated by optical and galvanomagnetic methods. The reaction constant for the reaction of neutral vacancy formation Hg(L) + VHgx 0 in Hg-saturated Hg1-xCdxTe crystals is determined in the temperature range 200...600°C. It is equal to (formula abailable in paper). Then defect diagrams for equilibrated mercury vacancies in Hg1-x CdxTe crystals of x = 0.215 and x = 0.295 are calculated. The results of calculations have coincided with the data of experiment. Concentration of equilibrated mercury interstitials HgI is estimated by studying mercury thermal diffusion in heterogeneous Te-saturated Hg1-xCdxTe crystals of x = 0.215 and x = 0.295. The reaction constant for the interstitial formation reaction Hg(L) yeilds HgI + 2e' is found for Hg-saturated conditions. It is equal to (formula available in paper) exp (-0.94 eV/kBT)cm-3 for x = 0.215 (formula available in paper). Basing on this data the reaction constant KF" for Frenkel's reaction HgI" + VHg" mutually implies 0 have been also obtained: KF" = 4.66•1046 exp (-2.26 eV/kBT) cm-6 for x = 0.215 and KF = 3.82•1045 exp (-2.19 eV/kBT) cm-6 for x = 0.295. Then total concentration of equilibrated mercury vacancies and interstitials in Hg 0.8Cd 0.2Te crystals have been calculated for Hg-saturated and Te-saturated annealing conditions in the temperature range from 0°C up to a melting point.
Formation of low-density InAs/InP(001) quantum dot arrays
Yuri I. Mazur, Heiko Kissel, Haeyeon Yang, et al.
Carrier transfer in low-density InAs/InP dot arrays with a multi-modal dot size distribution is studied by means of steady-state photoluminescence. The transition from saturation of the inter-dot carrier transfer to the unsaturated regime is surely observed by analyzing the shape of the luminescence signal for decreasing excitation densities. We unambiguously show that larger size dots provide a competing but saturable relaxation channel for smaller quantum dot ground states.
Status of molecular beam epitaxy of CdxHg1-xTe
A. P. Antsiferov, L. D. Burdina, Vasily S. Varavin, et al.
New generation of ultra high vacuum set, ultra-fast ellipsometer of high accuracy and automatic system for control of technological processes was produced for reproducibility growth of mercury cadmium telluride (MCT) solid solution heterostructures (Hs's) by molecular beam epitaxy (MBE). This system allows to grow MCT HS's on substrate up to 4" in diameter and used for future development technology of growth on Si substrate. The development of industrially oriented growth MCT HS's MBE on GaAs 2" in diameter is presented. The electrical characteristics of n-type and p-type MCT HS's MBE and uniformity of MCT composition over the surface area is excellent and satisfied for fabricating multielements arrays of high quality infrared devices.
Formation of InAs quantum dots in an aluminium oxide matrix by lateral selective wet oxidation
D. A. Tenne, O. R. Bajutova, A. K. Bakarov, et al.
Raman spectroscopy which provides valuable information on the structural parameters of QDs was used for monitoring of the lateral oxidation of InAs/AlAs QD structures and study of the phonon properties of InAs QDs in aluminium oxide matrix. Optical phonons of InAs QD's were found to be affected by both strain and confinement. Raman spectra measured from non-oxidized area reveal asymmetric lineshape of LO phonons in InAs QDs and demonstrate its low-frequency shift with increasing excitation energy that is explained by QD size distribution and phonon confinement in smaller-size dots. Raman spectra taken from oxidized area show an increase of the LO peak intensity and the shift of the phonon line position towards higher frequency. The first effect is explained by formation of wide bandgap aluminium oxide matrix that leads to the shift of confined electronic states in InAs QDs closer to the resonance with the laser excitation energy. The latter is caused by increasing mechanical strain in InAs QDs due to a shrinkage of the aluminium oxide layers. At the boundaries of oxidized/non-oxidized areas the presence of amorphous and crystalline As clusters is evident.
Chemical etching of CdTe and CdxHg1-xTe in the H2O2-HJ-tartaric acid solutions
Z. F. Tomashik, O. R. Gumenyuk, V. N. Tomashik
Kinetics of physico-chemical interaction of CdTe and CdxHg1-xTe solid solutions in the H2O2-HI-tartaric acid solutions in reproducible hydrodynamics conditions has been investigated. The main regularities of chemical etching and polishing of these semiconductor materials were determined and surfaces of equal etching rates (Gibbs diagrams) were built. Regions of polishing and unpolishing solutions were defined and etchant compositions for chemical dynamic polishing of CdTe and CdxHg1-xTe solid solutions and etching conditions were optimized.
Chemical dissolution of gallium antimonide in HNO3-HCl-CH3COOH solutions
O. S. Chernyuk, V. N. Tomashik, V. I. Grytsiv, et al.
The nature of GaSb dissolution in the mixtures of HNO3-HCl-CH3COOH system in reproducible hydrodynamics conditions has been investigated. The main regularities of chemical etching and polishing of GaSb, Sb and Ga were determined and surfaces of equal etching rates (Gibbs diagrams) were built. The potentials of self-dissolutions of indicated materials in the investigated solutions were studied also. Region of polishing solutions was defined and etchant compositions for chemical dynamic polishing of GaSb were optimized.
Schottky photodiode arrays on the basis of n-Pb1-xSnxTe1-ySey epitaxial layers, lattice-matched with {100}KCl substrates
O. N. Tsarenko, A. I. Tkachuk, S. I. Ryabets
The linear photovoltaic infrared sensor arrays have been formed on the basis of high-quality epitaxial layers of Pb1-xSnxTe1-ySey quaternary solid solutions, lattice matched with {100}KCl substrates, by the thermal vacuum deposition technique. Epilayers were grown from bounded volume of (Pb1-vSnv)1-w(Te1-uSeu)w melt-solutions by the liquid phase epitaxy technique at the liquidus temperature of 773 ÷ 873 K. The obtained 2 x 5-element matrix of the infrared photodiodes with the Au/δ-layer/n-Pb0.83Sn0.17Te0.79Se0.21 Schottky barrier at the 170 K, peak wavelength λp approximately 8.2 μm and cutoff wavelength λc approximately 8.8 μm had the zero bias resistance area product R0A=0.09 ÷ 0.22 Ω•cm2, peak quantum efficiency ηλ = 0.34 ÷ 0.45 and peak detectivity * = (0.6 ÷ 1.3)x1010 cm•Hz1/2•W-1.
SiOx thin films as material for uncooled microbolometer
K. Michailovskaya, Ivan Z. Indutnyy, Peter E. Shepeliavy
Composite metal-dielectric SiOx -Fe- films with concentration of metal varied on thickness in dielectric matrix SiOx are investigated. The reflectance and transmittance of the samples at normal incidence were measured in the 2 - 12 microns wavelength range. In the wavelength range of 2 - 8,5 microns absorption of the films is about 90%, in more long-wavelength area 8,5 - 12 microns absorption is equal 70 - 80%. The optical properties of these gradient layers are simulated, and the results of simulation are compared with experimental data. In a range of temperatures 283 - 390 K thermosensitive properties of SiOx -Fe- films are investigated and values of temperature coefficient of resistance is determined. These coatings can be used as a sensitive layer of uncooled microbolometers.