Surface Crystallization of Vitreous Selenium as Induced by Chemical Vapors

Crystallization of thin layers of vitreous Se induced by exposing the surface to various inorganic and organic solvent vapors, e.g., carbon disulfide, trichloroethylene, isopropyl acetate, has been studied at room temperature. It is noted that the morphology of the crystallites obtained and the various growth features observed are essentially the same for the different chemical vapors used and are similar to growth of Se crystals by evaporation. Different experimental conditions seem only to change the distribution of the relative abundances of the various morphologies and the time needed for achieving a certain extent of crystallization. The mechanisms of crystal growth in this case, as visualized through the various growth features at intermediate stages, are remarkably similar to growth by vapor deposition of Au and Ag films on single-crystalline substrates.