TRANSMISSION ELECTRON-MICROSCOPY INVESTIGATION OF THE POST-NUCLEATION GROWTH-STRUCTURE OF AMORPHOUS CADMIUM ARSENIDE THIN-FILMS

The post-nucleation growth structure of amorphous cadmium arsenide thin films prepared by physical vapour deposition was investigated by transmission electron microscopy and the carbon replica method. The very thin cadmium arsenide films exhibit a very distinct island structure. The islands and also the growth elements in thicker films are connected by pores or very low density areas. These density fluctuations were determined by deposition conditions mainly by rate of deposition and type of the substrate, but they were very stable on post-deposition heat treatment. The growth structure and its change with varying deposition conditions are considered qualitatively with the simple model where the growth structure evolves as a result of two superimposed growth stages, planar and in thickness.