DX-CENTERS IN IONIC SEMICONDUCTOR CDF2-GA

Analysis of thermally and optically induced transformations of metasta ble Ga centers in the wide-gap, predominantly ionic semiconductor CdF2 points to the existence of two metastable states of the center. The c onfiguration-coordinate model of the center is discussed and its energ y parameters are determined. It is concluded that this center is not j ust ''DX-like,'' as was initially assumed, but is a true DX center wit h a shallow donor and two deep negative-U states.