Effects of the preparation conditions and furnace annealing on the structure and morphology of Zn0.8Cd0.2Se thin films

Single layers of Zn_0.8Cd_0.2Se were prepared by thermal vacuum evaporation at room substrate temperature. Two groups of samples with the same composition were produced by applying consecutive deposition of ZnSe and CdSe sublayers with nominal thickness of 0.12 and 0.37 or 0.08 and 0.23 nm, respectively. Atomic Force Microscopy (AFM), Scanning Electon Microscopy (SEM) and X-ray diffraction (XRD) measurements were performed to explore the evolution of the crystal structure, microstructure, composition and surface morphology with the change of preparation conditions and upon furnace annealing of Zn_0.8Cd_0.2Se thin films (400nm) with various sublayer thickness at 673 K in an inert atmosphere. It has been found that as-deposited films were nanocrystalline with a grain size less than or around 5 nm and cubic structure. The variation of the sublayer thickness does not appreciably affect the film crystal structure and composition. Upon annealing the cubic structure is preserved, the average nanocrystals size increased and root mean square roughness strongly decreases.