Nonstoichiometry and point defects in nonlinear optical crystals A 2B 4C 25

Abstract

Using thermodynamic calculation, the equilibrium concentrations of point defects in ZnGeP 2 and CdGeAs 2 depending on a liquidus temperature are obtained. The conclusion about a high degree of compensation of native donors and acceptors is made. The methods of a model pseudo-potential and large unit cell are used for investigation of deep levels created by vacancies and antisites in the forbidden band of ZnGeP 2. Optical transitions with participation of the defects are defined. It is supposed the possibility of conditions favourable for mid-IR optical absorption, as a result of the interaction of ionized zinc vacancies with GeP clusters.