The temperature and energy dependence of photoinduced scalar phenomena in chalcogenide thin films

Temperature and energy dependence of thermal bleaching (TB) effect and photorefraction (PR) change, in chalcogenide As₄₀Ge₁₀Se_50-xS_x (x=0, 25, 35 at.%) thin films have been investigated. When these films were exposed for 15 min using the blue-pass filtered Hg lamp (~4300 Å) after annealing for 30 min around the glass transition temperature Tg (200°C), the stable characteristics of scalar effect were shown in As₄₀Ge₁₀Se₁₅S₃₅ composition, and in that composition the refractive index change Δ n was varied up to 0.02-0.46 according to each thickness conditions and the optical energy gap was shifted to a longer wavelength of approximately 0.67 eV, especially for 1000 Å-thickness. Also, in the case that light source was He-Ne laser, we could observe refractive index change Δ n and red-shift of absorption edge