Spectral dependence of photoinduced optical effects in AsSSe thin films

Abstract

Spectral dependence of photoinduced structural transformation and related changes of E g opt , α and n of thermally evaporated ternary As 40 S 60-x Se x thin films have been studied under the exposure to bandgap and super-/sub-bandgap light of LED. The irradiation by bandgap and super-bandgap light with intensity 0.1 W/cm 2 leads to partial photoinduced polymerization of molecular structural units into continuous network that is characteristic for the bulk glasses with appropriate stoichiometric composition. The efficiency of structural transformation depends on penetration depth of excitation beam. The maximum photosensitivity (i.e. changes of E g opt , α and n) were achieved at the wavelengths ~ 100 nm above the bandgap wavelength for each appropriate composition. Beyond the region of maximal photosensitivity the values of optical parameters and kinetics of photoinduced changes depend on relation between exposed and unexposed sublayer for super-bandgap beams or on absorption coefficient for sub-bandgap light.

Ternary CdS1–xSex nanocrystals formed in Cd‐doped As–Se–S films due to photoenhanced diffusion during micro‐Raman measurement

“…Note that earlier Raman studies of the amorphous As–Se–S systems in most cases presented data for the end‐point compounds and only one intermediate composition, [ 10,11,14 ] while a more detailed compositional behavior upon chalcogen substitution was analyzed in a quite limited number of studies for stoichiometric [ 13,17,57 ] and non‐stoichiometric [ 13,57 ] As–Se–S bulk glasses and thermally evaporated thin films. [ 15,16 ] The compositional behavior illustrated by Fig. 2 is in a good agreement with earlier data for stoichiometric As–Se–S bulk glasses [ 13,58 ] and thermally evaporated amorphous ternary As–Se–S films, the structure of which was relaxed by exposure to halogen lamp illumination.…”

“…2 is in a good agreement with earlier data for stoichiometric As–Se–S bulk glasses [ 13,58 ] and thermally evaporated amorphous ternary As–Se–S films, the structure of which was relaxed by exposure to halogen lamp illumination. [ 15 ] Fresh As–Se–S films, similar to As 2 Se 3 and As 2 S 3 , also exhibited both amorphous‐like and crystal‐like Raman features. [ 10,11,15 ] Meanwhile, Tasseva et al, [ 14 ] similar to our data, observed typically “amorphous‐like” spectra for As–Se–S films without additional annealing or exposure to light what could also be related to a sufficiently durable room temperature aging.…”

“…[ 15 ] Fresh As–Se–S films, similar to As 2 Se 3 and As 2 S 3 , also exhibited both amorphous‐like and crystal‐like Raman features. [ 10,11,15 ] Meanwhile, Tasseva et al, [ 14 ] similar to our data, observed typically “amorphous‐like” spectra for As–Se–S films without additional annealing or exposure to light what could also be related to a sufficiently durable room temperature aging. Detailed analysis of oscillators contributing to the Raman spectra of amorphous As–Se–S complemented by XPS and extended X‐ray absorption fine structure (EXAFS) data shows the possibility of the existence of mixed AsSeS 2 and AsSe 2 S pyramidal units in the amorphous As–Se–S structure.…”

“…[[ 1–4 ] and references therein] Less investigated are ternary systems of As–Se–S type. [ 10–17 ] Even fewer studies are devoted to materials of this kind doped with metal ions, which are interesting not only with the intention to understand doping‐induced changes in the local glass structure but also in view of potential applications. [ 11,14 ]…”

Study on crystallization behaviors of As–Se–Bi chalcogenide glasses

“…[1][2][3][4] ChG in similar compounds have also raised much interest for their large photosensitivity and a variety of photoinduced (PI) effects promising for photonic and optoelectronic applications in information storage, optomechanical transducers, etc. 5,6 The PI effects also can be observed in GeS 2 glasses and glass-ceramics in the visible and IR spectral range. 7 The photoinduced changes are considered to be associated with third order electronphonon anharmony and the electron-quasi-phonon interaction.…”