Kinetics of photoinduced surface patterning in chalcogenide thin films

The kinetics of photoinduced variations in surface profile in chalcogenide glass films under illumination is described. It is demonstrated that the competition between the stress-induced atomic flux (toward irradiated regions of the film) and the diffusion flux induced by an increase in the bulk energy due to broken bonds (and directed from irradiated to dark regions) can result in either a positive or negative net mass transfer in the irradiated region. Depending on the light intensity, one can obtain either formation of bumps or depressions in the illuminated regions.