STRUCTURE AND GROWTH OF EPITAXIAL PBSE FILMS

Epitaxial films of PbSe were vacuum-evaporated on to freshly-cleaved mica. The initial nuclei are of tetrahedral shape with (111) bases and (100) sloping faces. They are doubly positioned. Later, square nuclei with all (100) planes appear. During the growth and coalescence of nuclei, the film structure is considerably modified by recrystallisation, migration of domain boundaries and the removal of lattice defects. High deposition temperatures give rise to large nuclei with regular shapes, and during film growth, enhance a better structure containing large domains. The highest Hall mobility corresponds to the best film structure obtained at the optimum temperature (340°C). Lattice defects are present in lower temperature films, while higher temperature films contain small cracks. At sufficient thickness (order of microns) the structure can be so improved that the electrical mobility approaches that of the best bulk single crystals. © 1969.