D V Grigoryev

Analysis of efficiency of solar energy conversion by tandem CdxZn1-xTe/Si solar cell

In this work efficiency of solar energy conversion by solar cell based on tandem structure CdZnTe/Si is analyzed. It is shown that CdTe-CdZnTe-ZnTe material system is promising for creation of high-performance cascade solar cells.

Calculation of thermal parameters of SiGe microbolometers

The thermal parameters of a SiGe microbolometer were calculated using numerical modeling. The calculated thermal conduction and thermal response time are in good agreement with the values found experimentally and range between 2·10−7 and 7·10−8 W/K and 1.5 and 4.5 ms, respectively. High sensitivity of microbolometer is achieved due to optimization of the thermal response time and thermal conduction by fitting the geometry of supporting heat-removing legs or by selection of a suitable material providing boundary thermal resistance higher than 8·10−3 cm2·K/W at the SiGe interface.

Electrical Properties of the V-Defects of Epitaxial HgCdTe

The manufacturing process of wide-band-gap matrix photodetector devices and miniaturization of their individual pixels gave rise to increased demands on the material quality and research methods. In the present paper we propose using the methods of atomic-force microscopy to study the local distribution of electrical properties of the V-defects that form in epitaxial films of HgCdTe during their growth process via molecular beam epitaxy. We demonstrate that a complex approach to studying the electrical properties of a predefined region of a V-defect allows one to obtain more detailed information on its properties. Using scanning spreading resistance microscopy, we show that, for a V-defect when the applied bias is increased, the surface area that participates in the process of charge carrier transfer also increases almost linearly. The presence of a potential barrier on the periphery of individual crystal grains that form the V-defect interferes with the flow of current and also affects the distribution of surface potential and capacitive contrast.

Local distribution of the material composition in the V-defect region of HgCdTe epitaxial films

In this paper the local distribution of the material composition in the V-defect region of HgCdTe epitaxial films is investigated. The local composition distribution is studied by the Kelvin Force Probe Microscopy method and scanning electron microscopy with energy dispersive X-ray analysis. It is demonstrated that in the V-defect region of a Hg1-xCdxTe epitaxial film inhomogeneous distribution of the material component composition is observed. Analysis of the obtained experimental data shows that V-defects are distinguished by an increased mercury content.

Influence of the Plasma of Nanosecond Diffuse Discharge in Air at Atmospheric Pressure on the Electrophysical Properties of Epitaxial CdHgTe Films

In this paper the influence of the volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of CdHgTe (MCT) epitaxial films of p-type conductivity is investigated. Measurements of electro-physical parameters of MCT samples after irradiation have shown that a layer exhibiting n-type conductivity is formed in the near-surface area of epitaxial films. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. The obtained results show that application of volume nanosecond discharge in air at atmospheric pressure is promising for the modification of the surface properties of epitaxial films of MCT.

Investigation of the surface-potential distribution of epitaxial CdHgTe films

The epitaxial growth of CdHgTe films is accompanied by the formation of V defects whose density and electronic properties greatly affect the characteristics of a terminal device based on the given material. Scanning atomic-force microscopy techniques are proposed to investigate how electronic properties vary in the V-defect region of an epitaxial CdHgTe film. It is experimentally demonstrated that variations in the component composition of individual crystallites generating V defects create not only the complex spatial distribution of a potential field but also a potential barrier along the crystallite periphery. The given barrier must alter the charge-carrier exchange between crystallites, appreciably changing the current distribution over the V-defect area.

Impact of the nanosecond volume discharge in atmospheric pressure air on the distribution of the surface potential of epitaxial HgCdTe

In this paper we present the results of our research of the impact of nanosecond volume discharge on the electronic properties of the near-surface region of epitaxial Hg1−x Cd x Te films. We show that the distribution of the surface potential and, as a consequence, the material composition of the individual crystal grains that form V-defects possess a complex structure and contain regions with elevated content of both mercury and cadmium. The volume discharge treatment of the film surface leads to a decrease of the mercury content in individual crystal grains compared to the bulk of Hg1−x Cd x Te epitaxial film. This indicates a higher mercury desorption rate from the V-defect region.

Changes in the electro-physical properties of MCT epitaxial films affected by a plasma volume discharge induced by an avalanche beam in atmospheric-pressure air

In this paper the influence of the plasma volume discharge of nanosecond duration formed in a non-uniform electric field at atmospheric pressure on samples of epitaxial films HgCdTe (MCT) films are discussed. The experimental data show that the action of pulses of nanosecond volume discharge in air at atmospheric pressure leads to changes in the electrophysical properties of MCT epitaxial films due to formation of a near-surface high- conductivity layer of the n-type conduction. The preliminary results show that it is possible to use such actions in the development of technologies for the controlled change of the properties of MCT.

The impact of the plasma volume discharge in the atmospheric-pressure air on the distribution of the surface potential in a V-defect region of epitaxial HgCdTe films

In the present report we demonstrate the experimental data obtained as a result of studying the impact of nanosecond plasma volume discharge in the atmospheric-pressure air on the distribution of the surface potential in the V-defect regions of epitaxial HgCdTe films. The experimental data obtained for the variation of the contact potential difference (ΔCPD) between the V-defect and the main matrix of the epitaxial film show that the mean value of ΔCPD for the original surface differs from the one for the irradiated surface for 55 eV. At the same time the mean value of ΔCPD changes its sign indicating that the original surface of the epitaxial HgCdTe film predominantly contains the grains with increased cadmium content while after the irradiation the grains possess an increased content of mercury. Therefore, during the irradiation process a decrease of the mercury content in the near-surface region of the semiconductor takes place resulting in the alteration of the electrophysical properties in the films near-surface region.

Influence of pulsed nanosecond volume discharge in atmospheric-pressure air on the electrical characteristics of MCT epitaxial films

The purpose of this paper was investigating the effect of volume nanosecond discharge in air at atmospheric pressure on the electro-physical properties of the HgCdTe (MCT) epitaxial films grown by molecular beam epitaxy. Hall measurements of electro-physical parameters of MCT samples after irradiation have shown that there is a layer of epitaxial films exhibiting n-type conductivity that is formed in the near-surface area. After more than 600 pulses of influence parameters and thickness of the resulting n-layer is such that the measured field dependence of Hall coefficient corresponds to the material of n-type conductivity. Also it is shown that the impact of the discharge leads to significant changes in electro-physical characteristics of MIS structures. This fact is demonstrated by increase in density of positive fixed charge, change in the hysteresis type of the capacitance-voltage characteristic, an increase in density of surface states. The preliminary results show that it is possible to use such actions in the development of technologies of the controlled change in the properties of MCT.