"Soliton heteroepitaxy" in the formation of epitaxial films of II-VI compounds under highly nonequilibrium conditions

The broad spectrum of optical-electrical properties of the II - VI compounds has motivated a great interest to epitaxial films of these compounds. However, there still remains a field that has scarcely been included in the investigations: film formation from the vapor phase onto cooled substrates. It has been believed that epitaxial growth of I1-VI films is possible only on substrates heated to several hundred degrees centigrade [1 ]. The present investigation, whose results have been previously discussed in [2], demonstrates the possibility of epitaxy on substrates cooled to negative temperatures. Initial stages of the epitaxial growth of CdTe and CdS film on substrates cooled to the temperatures below 0 deg C are experimentally investigated. Electron diffraction patterns corresponding to the early stages of growth and photographs of the surface are presented. The experimentally revealed features (island size 20-25 nm, a 8-function size distribution of the islands, and a monotonic orientation process of the islands) are explained in the framework of a phenomenological theory of heterophase fluctuations and nucleation with the use of migration of solitons initiated by the misfit dislocations of crystal lattices.