PERCOLATION TRANSITION OF PERSISTENT PHOTOCONDUCTIVITY IN II-VI MIXED-CRYSTALS

We have observed for the first time conductivity fluctuations in the persistent photoconductivity mode in II-VI mixed crystals with the magnitude following the percolation approach as -T-TC-, where TC is the percolation threshold temperature. Experimental results have demonstrated that the random local-potential fluctuations induced by compositional fluctuations are responsible for the persistent photoconductivity observed in II-VI mixed crystals. Different behaviors resulting from the DX centers, the macroscopic barrier, and the random local-potential fluctuations are distinguished. © 1990 The American Physical Society.