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1

Energy-band diagrams and capacity-voltage characteristics of CdxHg₁₋xTe : based variband structures calculated with taking into account dependence of electron affinity on a composition

100%

Voitsekhovskii A. V. , Gorn D. I. , Nesmelov S. N. , Kokhanenko A. P.

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tom Vol. 18, No. 3

241-245

EN

The purpose of this scientific work is the research of energy-band diagrams and capacity-voltage characteristics of CdxHg₁₋xTe -based variband heteroepitaxial structures with taking into account the dependence of electron affinity on the composition. Numerical simulations of energy-band diagrams and capacity-voltage characteristics for metal-insulator-semiconductor structures based on CdxHg₁₋xTe -variable composition layers are carried out in this work. Energy diagrams are calculated with taking into account the dependence of electron affinity on the composition x of CdxHg₁₋xTe. This dependence was obtained in terms of dependence of the local electroneutrality level on the composition for CdxHg₁₋xTe.

2

Ion etching of HgCdTe : properties, patterns and use as a method for defect studies

75%

Izhnin I. I. , Mynbaev K. D. , Voitsekhovskii A. V. , Korotaev A. G. , Fitsych O. I. , Pociask-Bialy M.

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tom Vol. 25, No. 2

148--170

EN

Analysis is performed of the contemporary views on the effect of ion etching (ion-beam milling and reactive ion etching) on physical properties of HgCdTe and on the mechanisms of the processes responsible for modification of these properties under the etching. Possibilities are discussed that ion etching opens for defect studies in HgCdTe, including detecting electrically neutral tellurium nanocomplexes, determining background donor concentration in the material of various origins, and understanding the mechanism of arsenic incorporation in molecular-beam epitaxy-grown films.

3

Nanostructures with Ge–Si quantum dots for infrared photodetectors

75%

Izhnin I. I. , Fitsych O. I. , Voitsekhovskii A. V. , Kokhanenko A. P. , Lozovoy K. A. , Dirko V. V.

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tom Vol. 26, No. 3

195--200

EN

In this paper questions of optimization of growth conditions in the method of molecular beam epitaxy for creation of high-efficient quantum dot infrared photodetectors are considered. As a model material system for theoretical investigations, heterostructures with germanium-silicon quantum dots on the silicon surface are chosen. For calculations of the dependencies of quantum dots array parameters on synthesis conditions the kinetic model of growth of differently shaped quantum dots based on the general nucleation theory is proposed. The theory is improved by taking into account the change in free energy of nucleation of an island due to the formation of additional edges of islands and due to the dependence of surface energies of facets of quantum dots on the thickness of a 2D wetting layer during the Stranski–Krastanow growth. Calculations of noise and signal characteristics of infrared photodetectors based on heterostructures with quantum dots of germanium on silicon are done. Dark current in such structures caused by thermal emission and barrier tunneling of carriers, as well as detectivity of the photodetector in the approximation of limitation by generation-recombination noises are estimated. Moreover, the presence of dispersion of quantum dots by size is taken into account in the calculations of the generation-recombination noises. Results of calculations of the properties of structures with quantum dots and their dependencies on growth parameters, as well as the characteristics of quantum dot photodetectors are presented. Comparison of the estimated parameters of quantum dots ensembles and the characteristics of quantum dot photodetectors with experimental data is carried out.

4

Capacitance-voltage characteristics of MIS-structures on the basis of graded-band MBE Hg₁₋xCdxTe at passivation by epitaxially grown in situ CdTe

63%

Voitsekhovskii A. V. , Nesmelov S. N. , Dzyadukh S. M. , Varavin V. S. , Dvoretskii S. A. , Mikhailov N. N. , Sidorov Y. G. , Yakushev M. V.

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tom Vol. 18, No. 3

263-266

EN

The electrical properties of the interface between Hg₁₋xCdxTe (x = 0.22 and x = 0.32-0.36) and CdTe prepared in situ molecular beam epitaxy were estimated at 77 K. The methods of determination of main parameters of interface semiconductor/insulator and insulator from capacitance-voltage characteristics of MIS-structures based on graded-band Hg₁₋xCxTe have been developed. The fixed charge states density, fast surface states density, and density of mobile charge are obtained from capacitance-voltage measurements. For improvement in stable and electrical strength of insulator coating for several samples over CdTe additional protective layers SiO₂-Si₃N₄ are formed for x = 0.22 and ZnTe for x = 0.32-0.36.

5

Influence of near-surface graded-gap layers on electrical characteristics of MIS-structures based on MBE grown HgCdTe

63%

Voitsekhovskii A. V. , Nesmelov S. N. , Dzyadukh S. M. , Varavin V. S. , Dvoretskii S. A. , Mikhailov N. N. , Sidorov Y. G. , Yakushev M. V.

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tom Vol. 18, No. 3

259-262

EN

The paper examines influence of near-surface graded-gap layers on electrical characteristics of MIS-structures fabricated on heteroepitaxial Hg₁₋xCdxTe films grown by molecular beam epitaxy (MBE). Two types of insulators, i.e., two-layer SiO₂Si₃N₄ and anodic oxide films were used. As it is seen from the depth and width of the valley on the C-V characteristics, the capacitance is found to vary in a wide range, in contrast to the structures without graded-gap layers. It is shown that the graded-gap layer under MIS-structures with x = 0.22 effectively reduces the tunnelling generation via deep levels and increases a lifetime of minority carriers in the space charge region and its differential resistance. The properties of the HgCdTe-insulator interfaces are studied.