Photocapacitance relaxation and rigidity transition in GexAsxSe1-2x amorphous films

Abstract

The photocapacitance relaxation of GexAsxSe1-2x thin films is investigated for x=0.05, 0.07, 0.09, 0.14, 0.16, 0.18, 0.20 0.25, and 0.30. Compositional dependences of the low-frequency dielectric permeability, decay time constant and the Kohlrausch parameter of nonexponentiality are deduced from these data. All parameters show two compositional thresholds, one situated near the xc(1)=0.09, and the other near the xc(2)=0.16-0.18. These phase transitions have been identified in the bulk samples by means of a differential-scanning calorimetric method (P. Boolchand et al., Europhys. Lett., 52, p. 633, 2000).