Challenges of CW laser-induced crystallization in a chalcogenide glass

We report laser-induced modification of SbSI glass as a proof-of-concept of fabricating ferroelectric architectures in chalcogenide glasses. We observe structural (crystallization), chemical (evaporation of SbI3 and oxidation) and volume (contraction as well as expansion) changes under irradiation with a super-bandgap CW Ar+ laser due to the thermal runaway and photoexpansion effects. The crystalline grains grow, but in a very narrow range of applied laser power density (P) from 0.25 to 0.32 mW/μm2. At P>0.4 mW/μm2 SbI3 evaporation dominates and produces strong surface erosion. For P<0.2 mW/μm2 and long exposure times (1-10 min), only laser-induced expansion is observed.