The structure and growth of thin films of lead telluride and lead selenide condensed in vacuum on to amorphous substrates

Polycrystalline films of PbSe and PbTe up to 10 4 AA thick were condensed at 15 to 300 AA s -1 in residual air at 10 -3 to 10 -8 Torr pressure on to glass and polished stainless steel substrates, initially at room temperature, at normal and oblique vapour incidence. Surface structures were determined by high-energy electron diffraction at a series of film thicknesses. Distinct regions of different crystal orientation are identified dependent on film thickness, residual gas pressure and composition, deposition rate and the nature of the source material. The relationship between the angle of vapour incidence and the tilt of the orientation axis is also established. The influence of the experimental parameters on the development of the different orientation regions is discussed and the results are compared with similar results from PbS films.