Super-bandgap light stimulated reversible transformation and laser-driven mass transport at the surface of AsS chalcogenide nanolayers studied .

The super-bandgap laser irradiation of the prepared As-S chalcogenide films was found to cause drastic structural transformations and unexpected selective diffusion processes, leading to As enrichment on the nanolayer surface. Excitation energy dependent synchrotron radiation photoelectron spectroscopy showed complete reversibility of the molecular transformations and selective laser-driven mass transport during "laser irradiation"-"thermal annealing" cycles. Molecular modeling and density functional theory calculations performed on As-rich cage-like clusters built from basic structural units indicate that the underlying microscopic mechanism of laser induced transformations is connected with the realgar-pararealgar transition in the As-S structure.

Coherent Light Photo-modification, Mass Transport Effect, and Surface Relief Formation in AsS Nanolayers: Absorption Edge, XPS, and Raman Spectroscopy Combined with Profilometry Study.

As S (x = 40, 45, 50) thin films top surface nanolayers affected by green (532 nm) diode laser illumination have been studied by high-resolution X-ray photoelectron spectroscopy, Raman spectroscopy, optical spectroscopy, and surface profilometry. It is shown that the composition of obtained films depends not only on the composition of the source material but as well on the composition of the vapor during the evaporation process. Near-bandgap laser light decreases both As-As and S-S homopolar bonds in films, obtained from thermal evaporation of the AsS and AsS glasses.