A MORPHOLOGICAL AND STRUCTURAL STUDY OF EVAPORATED CADMIUM-SULFIDE THIN-FILMS

The morphology of evaporated cadmium sulphide thin film is investigated using scanning electron microscopy. As-grown films of thickness less than 30 nm exhibit protrusions which are identified with prisms developed along the c-axis. Pinholes and cracks in the films are also observed. The structure of the deposited films is interpreted and discussed in terms of line-profile analysis of X-ray diffraction patterns, with a particular emphasis given to the effects of preparation conditions on the orientation, crystallite grain size, and residual microstrain. The films are found to be of the hexagonal wurtzite structure with c-axis of length 0.6796 nm. All the films are found to be preferentially orientated with the <001> fibre texture. The degree of preferential orientation is found to increase slightly with increasing film thickness, but to decrease with increasing deposition rate. In general the grain size is found to increase with increasing thickness and to decrease with increasing deposition rate, while the residual microstrain shows the opposite dependence. The optimum temperature for the substrates during deposition appears to be approximately 150-degrees-C where the grain size is a maximum and the residual microstrain a minimum.