Raman scattering and photodarkening of amorphous Ge1-xSx (0 <= X <= 0.62) films

Amorphous Ge1-XSX films with Ge-rich composition of 0 less than or equal to X less than or equal to 0.62 were prepared by the laser ablation method to investigate the effect of sulfur on optical properties. From Raman spectra , it is found that the structure changes gradually with composition X. The change of properties from tetrahedral to chalcogenide semiconductors was ex amined in terms of photodarkening phenomena. As X increased, the photodarke ning effect began to be observed at X = 0.2 and enhanced significantly at X = 0.5. (C) 2000 Elsevier Science B.V. All rights reserved.