TEMPERATURE DEPENDENCE OF THE ELECTRICAL CONDUCTIVITY AND HALL EFFECT OF THALLIUM GALLIUM DISULPHIDE SINGLE CRYSTALS

Single crystal of the layered compound TlGaS2 were grown by direct synthesis of their constituents. Their electrical conductivity and the Hall effect was studied as a function of the temperature, both perpendicular and parallel to the layer planes, and their behaviour proved to be highly anisotropic. The Hall-effect measurements revealed extrinsic p- type conduction with an acceptor impurity level located at 0.586 eV for sigma(perpendicular to) and at 0.43 eV for sigma(//) above the valence-band maximum. The variation of the Hall mobility and the carrier concentration with temperature were investigated. The scattering mechanism of the carriers throughout the entire temperature range of investigation was checked. The anisotropic factor was also estimated, and its temperature dependence was illustrated.