Relation between Phase Memory Effect and Velocity of Trap-Controlled High-Field Domain in CdS

Abstract

The phase memory effect and the dependence of the domain velocity upon both the light intensity and the bias voltage are investigated in bulk and evaporated CdS. “Incomplete” phase memory effect is found in these CdS. It is found that the dependence of the domain velocity vd upon both the light intensity B and the bias voltage V is represented by vd=cBxVz (x=0.6∼1.0, z=0.7∼1.0, V>Vth), where c is a constant, and Vth is the threshold voltage of the domain formation. The dependence of the domain velocity is explained by assuming that the domain velocity is just the average effective velocity of all the photo-excited electrons. The phase memory effect is explained by this dependence. It is concluded that the mechanism of the phase memory effect must contain at least both the deep hole traps and the deep electron traps.