EFFECT OF COMPOSITION ON THE RATES OF PHOTODARKENING AND SILVER PHOTODOPING IN AMORPHOUS P-SE FILMS

Rates of photodarkening and photodoping of silver were examined in binary PxSe1-x amorphous films over a wide range from x=1 to 0.4. No monotonic change with x was observed for either of the rates. The photodarkening rate remained almost constant in the ranges of x<0.85, was reduced drastically by two orders of magnitude around x≊0.9, and became constant again in 0.95<x. A similar composition dependence was observed also for the photodoping rate. These results suggest that the presence of the critical composition in both rates is due to the change in the nature of uppermost orbitals of the valence band.