On the intrinsic nature of photocontraction effect in Ge-Se films

The nature of the gaint photocontraction effect observed in obliquely deposited thin films of Ge-Se has been investigated by various analytical techniques. It has been established that the observed contraction is entirely an intrinsic photooptical effect as long as the temperature during exposure does not exceed 80°C. At elevated temperatures, thermal evaporation, photooxidation and photoevaporation of selenium in the films takes place