Preparation and electrical characterization of the compound CuAgGeSe3

Abstract

This work reports the synthesis and electrical characterization of the compound CuAgGeSe3. This material was synthesized by direct melting of the constituent elements, in their stoiochiometric ratio inside an evacuated quartz ampoule. The chemical analysis (EDX) confirmed the 1:1:1:3 stoichiometric ratios for the compound. The differential thermal analysis showed the existence of a principal phase that melts at 558ºC and a second phase at 636 ºC. The X-ray powder diffraction analysis indicated that the compound crystallizes in the monoclinic system, space group Cc, with unit cell parameters: a = 6.776(0) Å, b = 11.901(5) Å, c = 6.772(0) and β = 108.2(0)o. The study of the electrical properties was realized in the temperature range from 80 to 300 K and under a magnetic field of 14 kG. Employing the Mott transition model, we were able to obtain the temperature dependence of the resistivity and we estimated that the activation energy is 25.3 meV in the low temperatures region. The mobility temperature dependence is analyzed by taking into account the scattering of charge carriers by acoustic phonons, polar optic phonons and thermally activated hopping. From the analysis, the activation energy is estimated to be around 38 meV and the characteristic temperature of the phonons is estimated to be around 400 K.