Structural and transport properties of [formula omitted] system (x = 2.5, 5.0, 7.5, 10.0 and 12.5)

Abstract

Polycrystals of Agx(Ga0.4Se0.6)100-x(x=2.5,5.0,7.5,10.0,12.5) were prepared by vertical Bridgman technique. The atomic composition and the structure of the crystals have been measured by energy dispersive analysis of X-ray (EDAX) method and X-ray diffraction analysis (XRD). X-ray diffraction analysis reveals that all samples were polycrystalline. Electrical and Hall Effect were investigated in the temperature range from 153 to 530 K. The electrical conductivity of the crystals (at room temperature) has been found to vary from 4.769 to 1.4308×10-8 (Ωcm)−1 for different compositions. The energy gap varied between 2.4 eV and 1.85 eV, the activation energy varied between 36.77 meV and 15 meV. During the experiments, different parameters have been obtained such as the mobilities, the concentration, the diffusion coefficient, the relaxation time, and the diffusion length for both minority and majority carriers. The thermal power factor, the electronic thermal conductivity, and the Figure of merit were also calculated for all compositions.