Nonstoichiometry problems of ZnSe: From single crystals to nanofilms

Selenium nonstoichiometry in ZnSe under bivariant and monovariant equilibriums was studied by a direct physical-chemical method. ZnSe single crystals grown from the melt and the vapor phase were used as starting materials. It was found out that at T > 720 K, overstoichiometric Se generates mainly electrically neutral defects. ZnSe thin films (50-300 nm) were prepared by vacuum thermal sputtering on “cold” glass substrates. To control the nonstoichiometry of the films, a specially designed two-chamber evaporator was used. The nonstoichiometry, electrical properties and morphology of the ZnSe films were investigated under various preparation conditions. It was demonstrated that it is possible to form p-n junction by varying the nonstoichiometry of ZnSe nanofilms.