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The results of studies of the electrical properties of InSe layered crystals hydrogenated from the gas phase are presented. Theoretical models for the description of the temperature dependences of the mobility and electron concentration of hydrogenated, undoped and annealed InSe crystals are proposed. In order to separately determine the effects of hydrogenation and conventional annealing, the studies of a vacuum heat treated sample under similar conditions were carried out. The electrical characteristics of single crystals were investigated in the temperature range 80/400 K. It is established that the electrical conductivity and free-electron concentration of hydrogenated InSe crystals significantly increased, and the electron mobility decreased. The increase in the conductivity and concentration is due to the ionization of the hydrogen atoms. The decrease in the mobility for hydrogenated and annealed InSe is due to the scattering of electrons by the localized hydrogen atoms as well as due to structural changes at annealing. It is shown that the dominant mechanisms of charge-carrier scattering that determine the temperature dependence of mobility are the scattering on homopolar optical phonons and the scattering on ionized impurities. In perfect undoped InSe single crystals, only the scattering on optical phonons occurs in the studied temperature range. The temperature dependence of the electron concentration is analyzed in the framework of the model of impurity conduction. We considered three types of impurity states in the band gap: the deep donor, shallow donor and acceptor. The energy and concentration of the levels were determined. The good coincidence of experimental and theoretical results confirms the validity of the chosen model for our materials. [ABSTRACT FROM AUTHOR]

The tensoresistance for the n-Ge single crystals uniaxially deformed along the crystallographic direction [100] in the region of intrinsic conductivity is investigated. Measurements were conducted for n-Ge samples, alloyed by Sb impurity, NSb = 5 Δ 1014 cm-3 concentration. The dependence of tensoresistance at temperatures T < 330 K has three characteristic regions. For the first region (at P < 0:8 GPa), the resistivity of n-Ge does not depend on the uniaxial pressure, since at such pressures there is a lack of the deforming redistribution of electrons between the L1 and Δ1 minima. For uniaxial pressures from 0.8 to 2 GPa (second region), the growth of the resistivity of n-Ge is explained by the decrease of an effective electron mobility due to the redistribution of electrons between the L1 and Δ1 minima with different mobility. A sharp decrease of the resistivity of n-Ge at uniaxial pressures P > 2 GPa (third region) is associated with an increase in the concentration of intrinsic carriers. The reduction of the resistivity of the investigated samples of germanium at temperatures T > 330 K is explained by the growth of the intrinsic carrier concentration of current. The features of the n-Ge tensoresistance and the non-linear growth of the electron concentration for such single crystals in the range of uniaxial pressures from 0.8 to 2.4 GPa are explained by the two-band mechanism of intrinsic conduction. The conduction band of germanium under such pressures becomes (L1 - Δ1)-type. A sharp decrease in the resistivity of n-Ge at uniaxial pressures P > 2:4 GPa is associated with an increase in the magnitude of the baric coeffient of the variation of the width of the band gap at the expense of (L1 - Δ1)-type inversion of the absolute minimum in germanium. The obtained results are important in the interpretation of various kinetic effects observed in highly deformed germanium single crystals and germanium-based nanostructures. Therefore, the results can be used for the creation of high-pressure sensors, heterostructures of SiGe, quantum dots of germanium. [ABSTRACT FROM AUTHOR]