T(z) phase diagram and optical energy gaps in CuGa(Se z Te1−z )2 alloys

Abstract

TheT(z) phase diagram of the system CuGa(Se z Te1-z )2 was obtained from x-ray diffraction and differencial thermal analysis (DTA) measurements. DTA measurements were carried out on each sample and the transition temperatures were plotted as a function of alloy composition. Values of lattice parameter were determined in all cases. Values of the optical energy gap at 300 K were obtained from optical absorption measurements, and these were analysed by using a recently proposed model which explains the downward bowing observed in the I-III-VI2 alloys.