The effect of metal dopants on photodarkening kinetics in amorphous AsSe and As2Se3 thin films

Photodarkening relaxation under light exposure of a-As2Se3 amorphous films doped with 0.5 at.% of metals Sn, Mn, Sm or Dy and a-AsSe films doped with Sn up to 10.0 at.% Sn was studied in dependence on the impurity and thermal treating. Both factors reduce photodarkening and the degree of reduction d epends on the type of impurity. The relaxation process may be described by a stretched exponential with the dispersion parameter 0.4 less than or equa l to alpha 1 and time constant increasing with embedding of impurity or the rmal annealing. The results are discussed in the frame of the recently forw arded "slip-motion" model of photodarkening in chalcogenide glasses.