Alexander V. Voitsekhovskii

Radiation defect formation in graded-band-gap epitaxial structures Hg1−xCdxTe after boron ion implantation

This paper describes experimental and modelling results of investigations of the dynamics of accumulation and spatial distribution of electrically active radiation defects when irradiating epitaxial films of Hg1−xCdxTe (MCT) with different graded-band-gap layers in the surface region of the material. The films, grown by molecular-beam epitaxy (MBE), were irradiated by B ions at room temperature in the radiation dose range 1011–3 × 1015 ions cm−2 with energies 20–150 keV and ion current densities from 0.001 to 0.2 µA cm−2. The results give the differences in implantation profiles, damage accumulation and electrical properties as a function of the variable composition of the films, the implantation energy and dose in the region of introduction of the implant. Comparison of the experimental results with various models shows good agreement. Analysis of the distribution of the electrically active defects in the irradiated material shows that the variation in the composition gradient in the implantation region does not have a marked effect on the migration of primary radiation defects.

Photodetectors and solar cells with Ge/Si quantum dots parameters dependence on growth conditions

In this paper recommendations for growth conditions necessary for achieving maximum detectivity of infrared photodetectors with quantum dots and efficiency of quantum dot solar cells are given. It is also shown that for improvement of photodetectors characteristics quantum dots should be grown at rather high temperatures, and, on the contrary, at relatively low temperatures for maximisation of solar cells efficiency.

Photoluminescence spectra of CdxHg1 − xTe quantum-well heterostructures

Photoluminescence spectra are measured for a nanoscale CdxHg1 − xTe heterostructure with a single quantum well about 12.5 nm thick in the case x = 0.24. The confined energy levels and the respective rates of different optical transitions are calculated on this basis. Major radiative processes are identified.

Stimulated Emission in CdHgTe Structures with Quantum Wells under Optical Pumping

This paper is devoted to the consideration of currently available studies on obtaining stimulated infrared emission in structures based on HgCdTe quantum wells. Also analysis and interpretation of discussed experimental results are presented in this article.

Differential conductance and capacity–voltage characteristics of MIS structures with single quantum wells based on HgTe

The paper presents research results of the admittance of metal–insulator–semiconductor (MIS) structures based on Hg1–xCdxTe grown by molecular–beam epitaxy (MBE) method including single HgCdTe/HgTe/HgCdTe quantum wells (QW) in the surface layer of the semiconductor structure. The thickness of a quantum well was 5.6 nm, and the composition of barrier layers with the thickness of 35 nm was close to 0.65. Measurements were conducted in the range of temperatures from 8 K to 200 K. It is shown that, for structures with quantum well based on HgTe capacitance, conductance oscillations in the strong inversion are observed. These oscillations are related to the recharging of quantum levels in HgTe.

Investigation of Ge/Si quantum dot structures using the methods of admittance spectroscopy

In this paper the properties of multilayer p–i–n–structures based on Si with Ge quantum dots fabricated by molecular beam epitaxy were investigated using the method of admittance spectroscopy at temperatures from 10 K to 300 K. The results of experimental research for two types of structures are presented. The activation energies of the emission process from localised states are calculated.

Photoluminescence of HgCdTe heterostructures with multiple quantum wells

An analysis of experimental data obtained by various authors via recording infrared (IR) photoluminescence (PL) in heteroepitaxial structures based on solid CdxHg1−xTe (CHT) solutions with multiple quantum wells is presented. A theoretical analysis of optical transition energies is conducted based on a self-consistent solution to the Poisson and Schröbinger equations for a quantum well. Experimental data obtained at different temperatures, pump powers, and excitation wavelengths are analyzed.

Researching photoelectric parameters of MCT MBE graded band-gap nanolayers with non-homogeneous composition and level of doping

Results of research electrophysical and photoelectric properties of HgCdTe photoconductive structures grown by method molecular beam epitaxy under influence of background radiation are submitted. Strong dependence of photoconductivity and carriers lifetime for a level of background radiation (for change aperture angle of diaphragm), which come to an agreement with results of calculation for the Auger mechanism of recombination are represented.

The boron implantation in the varied zone MBE MCT epilayer

In the paper experimental results on boron implantation of the CdxHg1-xTe epilayers with various composition near surface of the material are discussed. The electron concentration in the surface layer after irradiation vs irradiation dose and ion energy are investigated for range of doses 1011 - 3•1015 cm-2 and energies of 20 - 150 keV. Also the results of the electrical active defects distribution measurement, carried out by differential Hall method, after boron implantation are represented. Consideration of the received data shows, that composition gradient influence mainly on the various dynamics of accumulation of electric active radiation defects. The electric active defects distribution analysis shows, that the other factors are negligible.