Silver doped As₂S₃ chalcogenide films: A diffusion study

Abstract

Photo‐diffusion of silver across an As2S3 thin film layer is studied, as continuing some earlier work about surface morphology modifications in double‐layer structures of Ag and As2S3, and some qualitative preliminary results on lateral Ag diffusion in As2S3 thin films. An estimation of the Ag film's dissolution rate and the diffusion front's advancement rate in As2S3 is given based on cross‐section measurements. In order to understand better the diffusion mechanism of Ag in As2S3, a structural model of the As2S3 matrix is used to estimate the amount of silver which might be hosted by an As2S3 layer in terms of molar ratio, and an interaction mechanism of the Ag with the chalcogenide matrix is proposed (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Possible mechanism of Ag photodiffusion in a‐As2S3 thin films

“…4), compared to that given in Ref. 15. The values for the void's radius large enough to accommodate Ag species, like atoms or ions, are evidenced.…”

“…For the first stage – ascribed to the interface zone – we have already presented in a previous study 15 a four‐step diffusion mechanism of Ag in thin a‐As 2 S 3 films. Here we only recall in brief the improved milestones of this interface diffusion mechanism, before addressing the second stage of the diffusion, concerning the possible fate of the various Ag species penetrated further inside the amorphous chalcogenide film.…”

“…The photodiffusion of silver along with its complementary photodissolution phenomenon in binary chalcogenide films, like As 2 S 3 , As 2 Se 3 , Ge 30 Se 70 , etc. has been intensely studied and the results were reported in many papers throughout previous decades 1–15.…”

“…The diffusion rate has been estimated experimentally and a four‐step diffusion mechanism has been suggested for the Ag–As 2 S 3 interface region in Ref. 15.…”

Fabrication of uniformly dispersed nanoparticle-doped chalcogenide glass

“…[4][5][6] However, in conventional photodoping procedures, which rely on thermal evaporation and sputtering to create a thin layer of metal on top of the chalcogenide film, the thickness of the doped layer is limited by the diffusion depth of the silver. 7 Also the uniformity of the doped layer is difficult to control, thereby setting limitations in fabricating application-favorable bulk structures.…”