Coexistence of fast photodarkening and slow photobleaching in Ge19As21Se60 thin films.
We experimentally demonstrate the coexistence of two opposite photo-effects, viz. fast photodarkening (PD) and slow photobleaching (PB) in Ge(19)As(21)Se(60) thin films, when illuminated with a laser of wavelength 671 nm. PD appears to begin instantaneously upon light illumination and saturates in tens of seconds. By comparison, PB is a slower process that starts only after PD has saturated. Both PD and PB follow stretched exponential dependence on time. Modeling of overall change as a linear sum of two contributions suggests that the changes in As and Ge parts of glass network respond to light effectively independent of each other.
Department of Physics, Indian Institute of Science Education and Research, Bhopal 462023, India.
Pritam
P
Khan
A R
AR
Barik
E M
EM
Vinod
K S
KS
Sangunni
H
H
Jain
K V
KV
Adarsh
D008027:Light; D008567:Membranes, Artificial; D008670:Metals / Q000737:chemistry*; D038761:Photobleaching; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation
D008567:Membranes, Artificial; D008670:Metals