semiconductors

On the example of semiconductor crystals Ge, Si, PbTe, PbS, InSb with different levels of doping and different types of conductivity, the geometry of the piezoresistive effect was optimized, namely, such directions of voltage measuring and uniaxial pressure applying were determined, which ensure the maximum achievable value of the effect. The optimization is based on an approach using the construction and analysis of extreme surfaces that represent all possible maxima of the objective function (the magnitude of the effect) under different spatial orientations of interacting factors.

The quantum-chemical modeling of the synthesis process chemistry of CdS and CdSe in aqueos solutions was carried out. For that reason, the CdS synthesis simulation was carried out through the formation of Cd(II) complex forms with the trisodium citrate and ammonium hydroxide. At the CdSe synthesis, the sodium selenosulfate with and without trisodium citrate was used. It was established that this process passes through several intermediate stages with the transitional reactive complexes formation.

The quantum-chemical modeling of the synthesis process chemistry of ZnS and ZnSe in aqueos solutions was carried out.For modeling the simulation of ZnS synthesis was made through the formation of Zn(II) complex forms with the trisodium citrate, sodium hydroxide and the pair of ammonium hydroxide with hydrazine hydrate. For the synthesis of ZnSe was used only sodium hydroxide.It was established that this process passes through several intermediate stages with the transitional reactive complexes formation.

The HgS and HgSe films were obtained by chemical deposition technique from an aqueous solution of mercury(II) salt, complexing and chalcogenizing agents. For the obtaining of Hg(II) complexes during the HgS films synthesis thiourea was used, and during the HgSe films synthesis – potassium iodide, potassium rhodanide and sodium thiosulfate. By the X-ray phase analysis was confirmed the formation of desired compounds, as well as the formation of Hg3I2Se2 ternary compound in the case of potassium iodide use during the synthesis of HgSe films.

The As2Se3-Tl3As2S3Se3 system was studied using differential thermal analysis, powder X-ray diffraction, as well as microhardness and density measurements and its phase diagram was constructed. The studied system contains a new quaternary compound ТlAs2Sе3S, which crystallizes in tetragonal structure. The temperature dependence of the electrical conductivity of alloys was studied.