Photo-oxidation of As2Se3, Ag–As2Se3, and Cu–As2Se3 chalcogenide films

Photoinduced effects in AsSP glasses

“…The shape of photoexpanded surface is associated with a laser Gaussian profile as already shown by Ogusu et al [17]. The phenomenon is explained by photooxidation [18] together with photoexpansive force.…”

Dependence of photo-oxidation on Ag(Cu)-content in Ag(Cu)–As2Se3 films

“…However, such photoinduced phenomena can be sometimes detrimental for a variety of applications. Therefore, we recently investigated photo-decomposition and photo-oxidation reaction (i.e., the formation of As 2 O 3 microcrystals) in As 2 Se 3 , Ag-doped As 2 Se 3 (i.e., Ag x (As 0.4 Se 0.6 ) 100Àx and we hereafter express it as AgAs 2 Se 3 ) and Cu-doped As 2 Se 3 films, and showed that the addition of metals Ag or Cu into As 2 Se 3 films weakened or eliminated such a photo-oxidation reaction [16]. Since this conclusion has been given at a silver content of 3.1 at.% and a copper content of 2.4 at.%, we must investigate the dependence of the photo-oxidation on Ag(Cu) content from a practical viewpoint.…”

“…Although the preparation of samples, the experimental setup, and the experimental conditions have been in detail described in the previous paper [16], for the sake of completeness we describe them briefly. An As 2 Se 3 film was first deposited on a glass slide by vacuum evaporation at a rate of 3 nm/s.…”

“…The thickness of all the As 2 Se 3 films used in the experiment was $1.3 lm, which was determined using the Swanepoel method [24]. A silver or copper layer was then evaporated on the top of the As 2 Se 3 film by a thickness corresponding to a certain desired value of Ag (Cu) content and they were photodoped into the host film with light from a 500-W tungsten lamp through a Fresnel lens [16,25]. We did not use an IR cut filter to make use of thermally-induced diffusion in addition to the photo-diffusion.…”

“…In relation to the photo-oxidation reaction, we also pay attention to the appearance of photodarkening effect since the two phenomena are expected to be related to each other through photoinduced changes in structure. The experiment was carried out by use of the identical experimental setup and conditions that were done in our previous work [16]. Although the observation of As 2 O 3 microcrystals has been reported by many authors [17][18][19][20][21][22][23], there is not such an attempt as done in the present work.…”