Donor compensation in the depletion layer of CdF2 crystals with a Schottky barrier

RF response and capacitance-voltage and current-voltage characteristics of n-type semiconductor crystals CdF2:In, CdF2:Ga, and CdF2:Y with a Schottky barrier were studied. Specific features of these characteristics are accounted for based on the assumption that the charge transport from the metal to the depletion layer is due to the formation of Cd0 excitations in the contact layer, which occurs because of the supply of electron pairs from the metal (Au). These excitations compensate donors in the space-charge region of ∼1 µm thickness, adjacent to the contact.