PHOTODENSIFICATION IN AMORPHOUS P-SE THIN-FILMS

The photoinduced shift in the absorption edge, changes in optical constants, film thickness contraction and rate of chemical dissolution were investigated for P-Se thin films deposited under normal (0 degree ) and oblique (80 degree ) incidence. These studies confirm authors' view that a variety of photoinduced phenomena observed earlier in germanium- and arsenic-based chalcogenides are primarily due to the chalcogen sulfur and/or selenium and that the role of germanium, arsenic or phosphorus is to act as matrices to stabilize a low density glassy structure. An irreversible thickness contraction of about 5% was found in films of P//4Se//1//0 deposited at 80 degree and is due to the decrease in the void volume on band gap irradiation. The thickness contraction was used for the generation of high resolution relief patterns.