Electrical structure of the surface of real crystal substrates as the determining factor of the growth stage in epitaxy

Abstract

The electrical structure of cleavage surfaces of triglycine sulphate (TGS), NaCl and mica crystals has been studied on the scale of optical microscopy by the method of selective crystallization of anthraquinone. Decoration of the TGS cleavage surface showed that on positively charged domains the needle shaped crystals of anthraquinone form a uniaxial texture, while on the surface of negatively charged domains a biaxial texture arises. Comparison of decoration pictures from TGS cleavages with those from NaCl and mica indicates that positively and negatively charged regions, ranging in size from 50 to 500 microns, are present on the surface of NaCl and mica real crystals. These regions differ from one another, in the magnitude of charge and potential. Possible reasons for the occurrence of volumetric and surface electrical heterogeneity in real NaCl and mica crystals are considered. The nature of the growth of anthraquinone crystals is primarily accounted for by the electrical structure of the surfaces of the crystalline substrates. A general conclusion is made that crystallization at the growth stage (as well as at the nucleation stage) is programmed by the electrical structure of the crystal surfaces. Thus, the processes of crystallization should hence be considered as matrix replication processes.