Preparation and properties of GaSxSe1–x solid solutions

Abstract

Single crystals of the composition GaSxSe1–x, with 0 ≦ x ≦ 1, have been obtained from the vapour using the “iodine assisted transport method” and from the melt using the “Bridgman-Stockbarger method”. The former method gives mainly platelike crystals with dimensions depending on the chemical composition. By the latter method one obtains single crystal ingots, the perfection and orientation of which depends on the growth conditions. The chemical composition of the crystal obtained in each growth run has been determined by atomic absorption spectrometry. Precise optical absorption measurements, carried out at room temperature, show that both direct and indirect energy gaps vary linearly with x. Slight energy differences result between melt and vapour grown crystals in the range 0 ≦ x ≦ 0.4. A comparison of the obtained results indicates that melt growth is preferable in the preparation of GaSxSe1–x solid solutions.