Sub‐Gap Photo‐Induced Phenomena in Chalcogenide Glasses

Photo-induced phenomena in chalcogenide glasses

“…For instance, using As 2 S 3 (E g ≈ 2.4 eV) and 2.0 eV photons (Tanaka, 2003b), we can produce giant volume expansions (Hisakuni and Tanaka, 1994) and bulky fluidity (Hisakuni and Tanaka, 1995). Note that the excitation lies in the Urbach-edge region ( Fig.…”

“…6.8, attract considerable interest for two reasons (Tanaka, 2006). The first stems from a fundamental question: why can the sub-gap excitation induce more prominent changes (Tanaka, 2003b), under some circumstances, than those induced by bandgap excitation?…”

Photostability of pulsed laser deposited amorphous thin films from Ge-As-Te system

“…In an earlier work, Tanaka 23 claimed that the band gap (and super band gap) irradiation affects with higher efficiency lone pair electrons of chalcogen atoms (which are supposed to be responsible for photoinduced phenomena) than the sub band gap light. Our results do not correlate completely with this statement.…”

“…It should be mentioned that a phenomenological description of the photoinduced effects in amorphous chalcogens and chalcogenides is often given by configuration-coordinate models 1 23 31 , which propose the ground state of the system formed by a double-well potential with an energy barrier separating the ground and metastable states. After the photoexcitation, the system is transferred to the metastable state, where (after electronic relaxation), the electron and hole are trapped in the conduction-band tail state and in the valence-band edge state, respectively.…”