Microstructural and surface morphological studies on Co doped ZnS diluted magnetic semiconductor thin films

Abstract

Microstructural and surface morphological studies of Co (2.5%) doped ZnS thin films deposited at different substrate temperatures (TS) of 200, 400 and 600 °C by means of pulsed laser deposition are presented. The deposited films are in wurtzite-hexagonal crystal structure as confirmed by X-ray diffraction and Raman spectroscopy techniques. The films deposited at higher TS show columnar morphology, as evidence by transmission electron microscopy measurements. Images of the surface topography have been taken by atomic force microscopy (AFM) for the film deposited at different TS. The film deposited at TS of 200 °C shows cone-like structures while deposited at TS of 400 and 600 °C show columnar structures. A fractal analysis has been performed on AFM images to understand the microstructure and surface morphology of thin film at different TS. Fractal analysis also reveals the morphological changes in the film with increasing TS. The observed ferromagnetism is correlated with columnar growth of the film which can be used as diluted magnetic semiconductor for spintronic applications.