Studies on ageing and electrical conduction in CdSe(0.2)Te(0.8) thin films

The stability of the film resistance in various ambients and the dependence on thickness, deposition temperature, deposition rate and heat treatment in vacuum were investigated for CdSe(0.2)Te(0.8) thin films. Unlike for other CdSe(x)Te(1-x) thin films with higher mole per cent CdSe, the film resistance remained steady in oxygen and in air atmospheres. The improvement in film conductivity with increase in deposition temperature, deposition rate and heat treatment in vacuum may be attributed to the increase in excess Te in the p-type film. Film crystallinity increased with increasing film thickness and deposition temperature and decreased with increasing deposition rate as shown by transmission electron micrographs (TEM) of the films. The improvement in film conductivity with increase in film thickness may be explained by Seto's polycrystalline model. © 1990.