PHYSICAL PROPERTIES OF SUBLIMATED TERNARY COMPOUND CdZnS THIN FILMS

Abstract

Mechanically mixed Cadmium Sulphide (CdS) powder with Zinc (Zn) (99.9% purity) was used as a source material to sublimate a ternary compound of Cadmium Zinc Sulphide (CdZnS) by using Closed Space Sublimation (CSS) under high vacuum. Annealing was carried out under optimized temperature and time for better diffusion of Zn into CdS. Xray diffraction (XRD) studies revealed that (002) was preferred orientation with hexagonal phase after annealing. Crystallite size of prepared films increased from 17 to 89 nm after annealing at higher temperatures. The surface morphology of the films was changed and the average composition of elements was confirmed by energy dispersive X-rays (EDX). The optical band gap energy increased from 2.42 eV and 2.45 eV after annealing. Electrically, the variation in mobility and increase in carrier concentration was due to the decrease of the grain boundary region. There was also variation in activation energy which confirmed the improvement in structure.