Influence of thermal history on the photostructural changes in glassy As15S85 studied by Raman scattering and ab initio calculations

Photostructural changes—the hallmark of non-crystalline chalcogenides—are in essence the basis of a number of photoinduced effects, i.e., changes of their physical properties, which are exploited in a variety of applications, especially in photonics and optoelectronics. Despite the vast number of investigations of photostructural changes, there is currently lack of systematic studies on how the thermal history, which affects glass structure, modifies the extent of photostructural changes. In this article, we study the role of thermal history on photostructural changes in glassy As15S85. This particular sulfur-rich composition has been chosen based on the colossal photostructural response it exhibits under near-band gap light irradiation, which inherently originates from its nanoscale phase-separated nature. To control the thermal history, the glass was quenched to various temperatures and each of these quenched products was annealed under four different conditions. Off-resonant Raman scattering was used t...