Synthesis, structure and electrical properties of Li+-doped pyrochlore Gd2Zr2O7

The pyrochlore Gd1.55Li0.45Zr2O6.55 was prepared by the solution and solid-state methods. The introduction of lithium in the Gd-sublattice led to decrease in the lattice parameter a = 10.4830(8) Å in comparison with Gd2Zr2O7 (a =10.5346(2) Å). Monitoring of the lithium content in the sample during heat treatments showed a loss of lithium at temperatures above 1100 °C, so, to maintain the stoichiometry of lithium the low temperature sintering methods are required. The sample Gd1.55Li0.45Zr2O6.55 exhibited a predominant oxygen-ion transport over a wide range of temperatures. Although doping did not lead to an increase in the oxygen-ion conductivity compared to Gd2Zr2O7, it caused the suppression of the hole conductivity.

Двух- и трехфотонный линейно-циркулярный дихроизм в полупроводниках кубической симметрии

The linear-circular dichroism of two and three photon absorption of light in semiconductors of cubic symmetry of hole conductivity is theoretically investigated. The matrix elements of two and three-photon optical transitions occurring between the subbands of the semiconductor valence band are calculated. In this case, transitions associated with both non-simultaneous absorption of individual photons and simultaneous absorption of two photons are taken into account, and the spectral and temperature dependences of the coefficient of two and three-photon absorption of polarized radiation are determined.

Two and three photonic linear circular dichroisms in semiconductors with cubic symmetry

The linear-circular dichroism of two and three photon absorption of light in semiconductors with cubic symmetry of hole conductivity is theoretically investigated. The matrix elements of two and three-photon optical transitions occurring between the subbands of the semiconductor valence band are calculated. In this case, transitions associated with both non-simultaneous absorption of individual photons and simultaneous absorption of two photons are taken into account, and the spectral and temperature dependences of the coefficient of two and three-photon absorption of polarized light are determined.

Investigation of Electronic Conductivity in PbI2:Hf Single Crystals

A study of the electron-hole conductivity in PbI2 single crystals doped with Hf (0.2 wt %) was conducted using the Wagner polarization cell method. The influence of the Hf alloying admixture (0.2 mass%) on the nature and parameters of lead diiodide’s electronic conductivity has been analyzed. Basing on the received current-potential dependences, p-type conductivity of a single crystal PbI2:Hf was established. The hole conductivity values (sро) were determined in the studied temperature range allowing to construct temperature dependence. The sро value for single crystal PbI2:Hf increased responsively to increasing temperature. For PbI2 and PbI2:Hf, a comparative analysis of the electron-hole conductivity was carried out. This investigation allowed determining the activation energy sро reduction from 0.47 eV to 0.32 eV due to hafnium doping. Consequently, the presence of Hf admixture in PbI2 crystals causes new impurity acceptor levels located at a distance of 0.64 eV from the upper limit of the valence zone.

Electro-Physical Properties of Ge-doped Cd1-xMnxTe (x < 0.1) Crystals

Ge-doped Cd1-xMnxTe (x = 0.02, 0.04, 0.08) crystals were grown by the Bridgman method. Carried out electrical measurements in the temperature range 280 – 420 K have found that the crystals’ hole conductivity is controlled by the deep compensated acceptors, whose ionization energy (εA) was increased with the content Mn (x) according to the relation εA = 0.6 (1 + 2х) eV. At 300 K: ρ = (108-109) (Ohm´cm), RH = (5×109-5×1010) cm3/C; mobility of current carriers ~ 50 cm2 /(V´s).