EPR characterization of optical-quality AgGaS2 grown from the melt

Abstract
The EPR study of optical‐quality AgGaS2 has proven the existence of the point defects Ni3+, Fen+, (n⩽2), a shallow donor (ED3+‐X, the charge states of which are all photosensitive. The effectiveness of the standard annealing procedures, employed to obtain crystals of low absorption in the 0.5–12‐μm range, is associated with an oxidation of these transition‐metal impurities.