Influence of Ga incorporation on photoinduced phenomena in Ge–S based glasses

Abstract

a b s t r a c tTo study the influence of Ga addition on photoinduced effect, GaGeS glasses with constant atomic ratio S/Ge = 2.6 have been prepared. Using Raman spectroscopy, we have reported the effect of Ga on the structural behavior of these glasses. An increase of the glass transition temperature T g , the linear refractive index and the density have been observed with increasing gallium content. The photoinduced phenomena have been examined through the influence of time exposure and power density, when exposed to above light bandgap (3.53 eV). The correlation between photoinduced phenomena and Ga content in such glasses are shown hereby.

Local motifs in GeS2–Ga2S3 glasses

“…These works also use several different methods such as Raman [12,[36][37][38][39], XAFS [40], neutron diffraction [41], EXAFS [42], XRD and Raman [43], 2D micro-Raman [44]. They have all found that Ge and Ga atoms are equally fourfold coordinated, [GaS 4 ] and [GeS 4 ] tetrahedral units are cross-linked via bridging sulfur atoms, M-chalcogen bonds are preferable.…”

Oxygen assisted photoinduced changes in Ge39Ga2S59 amorphous thin film

“…Fig. 5A, B and C, belongs to the stretching of S-S bonds in S n chains or S 8 rings, see for instance [8,14]. The RF(470) can probably be assigned to the bending modes of Ge-O-Ge (≈556 cm −1 ) or to the breathing motion of oxygen in the GeO 4 ring (≈520 cm −1 ) [20] if a disorder in the film network, the inclusive presence of S x O 3−x Ge-O-GeO 3−x S x units, leads to an increase in the Ge-O-Ge valence angle, to a decrease in corresponding force constants and hence to the shift of this RF by about 60 cm −1 to the lower wavenumber.…”

“…For photoexpansion in Ge-S binary glasses, the presence of Ga atoms is suggested to be essential because just photooxidation leads to formation of (Ge/Ga)-O units inducing photoexpansion [8]. From a number of studies it is evident that (i) the blue light supports photooxidation of amorphous chalcogenide films and (ii) photooxidation of amorphous chalcogenides is an interesting process which could significantly and dynamically modify the surface, near surface states and even, depending on the actual conditions of photooxidation, the volume properties of the films [3][4][5][6][7][8]. Moreover, it seems that compositional and structural changes associated with photooxidation "can be applied to in situ formation of materials with a new structural organization" [7].…”

“…This chemical composition was selected because the presence of Ga atoms is claimed to be essential for photooxidation [8] and hence it is interesting to know whether the amorphous film with a quite small content of Ga will be photooxidized by UV photons. Using classical optical transmission measurements in the region of the short wavelength edge the changes of the optical band gap and the thicknesses induced by illumination or by annealing of the film prepared were estimated.…”

Free‐volume nanostructural transformation in crystallized GeS2–Ga2S3–CsCl glasses

“…There are many experimental techniques to study the atomic void structure of solids, but they are lim-ited at the sub-nanometer scale [8][9][10][11]. One of the informative tools used to identify and study internal free volumes in various materials is positron annihilation lifetime (PAL) spectroscopy [12,13].…”