Growth of zinc sulfide thin films on (100)Si with the successive ionic layer adsorption and reaction method studied by atomic force microscopy

Zinc sulfide (ZnS) thin films were grown on (100)Si substrates from solution with the successive ionic layer adsorption and reaction (SILAR) method. Aqueous solutions of ZnCl2 and Na2S were used as precursors. The morphological development of the films with increasing number of SILAR cycles was monitored ex situ by atomic force microscopy (AFM) operated in tapping mode. Their roughness increased vs. the growth cycles. AFM studies on (100)Si substrates treated with Na2S solution revealed that the dissolution of the silicon substrates is a process competing with the thin film growth and has to be considered when interpreting the AFM images.