The kinetics of the photo-induced solid-state chemical reaction in Ag/As<sub>33</sub>S<sub>67</sub>bilayers and its reaction products

Wágner, T.; Márquez, E.; Fernández-Peña, J.; González-Leal, J.M.; Ewen, Peter; Kasap, S. O.

doi:10.1080/13642819908206794

Cited by 31 publications

(14 citation statements)

References 22 publications

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“…Two diffusion processes were also observed in modulated optical reflectivity measurements of silver photodiffusion in the Ag/Ag-S system [8]. In addition, the result is consistent with that reported by one of the authors (MM) in which modeling of Ag transport in Ge-Se glass showed the presence of both slow and fast moving Ag ions [17].…”

Section: Silver Diffusion Processsupporting

confidence: 82%

“…Until now, it has been thought that the diffusion front in these systems advances continuously as the sample is illuminated, stopping only when the silver layer is exhausted or, when reaching the end of the film. This model of diffusion is based on numerous previous studies, which used mainly two types of experimental technique: the measurement of time-dependent changes in properties, such as electrical resistivity [6] and optical reflectivity [7,8]; and, the determination of detailed concentration profiles using Rutherford backscattering [5,[9][10][11]. Using this latter approach, Rennie et al [10] conducted in situ Rutherford backscattering measurements during illumination of the sample to eliminate the possibility of thermal diffusion.…”

Section: Introductionmentioning

confidence: 98%

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Studies of silver photodiffusion dynamics in Ag/Ge_xS_1−x(x= 0.2 and 0.4) films using neutron reflectometry

et al. 2014

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To better understand the dynamics of silver photodiffusion into amorphous chalcogenide (Ch) films, it is informative to probe the time-dependent distribution of silver in the films while they are simultaneously exposed to visible light. Timeresolved neutron reflectometry is particularly well-suited to this purpose because it can follow time-dependent changes in the multilayer structure (Ag/Ag-Ch/Ch) while excluding the possibility of probe beam induced changes. This paper reports the results of time-resolved neutron reflectivity measurements of two Ag/Ge x S 1−x (x = 0.2 and 0.4) films as they are exposed to a visible light source. Analysis showed that silver diffusion occurs via two distinct processes: a fast diffusion that takes place during the first 2 and 10 min of sample illumination for the x = 0.2 and 0.4 films, respectively; and a subsequent slower change that is observed over the next 18 min (x = 0.2 film) and 107 min (x = 0.4 film). These results suggest the formation of a relatively stable Ag-rich phase in the reaction layer followed by slower diffusion at the interface between Ag-rich and Ag-poor layers. Fourier transform analysis shows that the position of the interface is essentially fixed -a conclusion that contradicts the "diffusion front" model that has been previously postulated. PACS Nos.: 82.50.Bc, 78.47.D, 61.05.fj.Résumé : Afin de mieux comprendre la dynamique de la diffusion de Ag induite par radiation dans les films de chalcogénure amorphe (Ch), il est instructif de sonder la variation dans le temps de la densité de Ag pendant l'irradiation en lumière visible. La réflectométrie de neutrons à résolution temporelle est particulièrement bien adaptée à cette fin, parce qu'elle permet de visualiser la variation dans le temps dans une structure multicouches (Ag/Ag-Ch/Ch), tout en excluant un effet dû à la sonde elle-même. Nous présentons ici les résultats de nos mesures dans le temps sur deux couches Ag/Ge x Si 1−x , pour x = 0.2 et 0.4, lorsqu'exposées à la lumière visible. L'analyse montre que la diffusion de l'argent se produit selon deux mécanismes différents : une diffusion rapide se produit pendant les 2 et 10 premières minutes pour les films x = 0.2 et 0.4 respectivement et une seconde diffusion plus lente est observée durant les 18 et 107 minutes subséquentes pour les films x = 0.2 et 0.4 respectivement. Ces résultats suggèrent la formation d'une phase riche en Ag relativement stable à la couche de réaction, suivie par une diffusion plus lente à l'interface entre les couches riche et pauvre en Ag. L'analyse par transformée de Fourier montre que la position de l'interface est essentiellement fixe, un résultat qui contredit le modèle du front de diffusion précédemment postulé. [Traduit par la Rédaction]

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Section: Silver Diffusion Processsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 98%

Studies of silver photodiffusion dynamics in Ag/Ge_xS_1−x(x= 0.2 and 0.4) films using neutron reflectometry

et al. 2014

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“…A study on the reaction rate is also important to understand the mechanism of silver photodiffusion. So far, the time-dependence of the amount of Ag or reaction products was investigated by X-ray diffraction, 15 optical measurement, 10,11,13,22 RBS, 18 and electrical resistivity. 8,9 Basically, the reaction curve markedly depends on the Ch composition, and it would not be easy to describe a unified reaction process.…”

Section: Photo-induced Kineticsmentioning

confidence: 99%

“…So far, there have been considerable investigations on the kinetics of silver photodiffusion. Many different studies have been utilized to give information about how Ag ions diffuse into the chalcogenide (Ch) layer-from electrical resistivity measurement, 8,9 optical transmittance measurement, 10 modified optical reflectivity measurement, [11][12][13] X-ray diffraction measurement, 14,15 to Rutherford backscattering (RBS). [16][17][18][19][20][21][22] Among these techniques, electrical resistivity and X-ray diffraction are good tools to evaluate the Ag thickness, but it is difficult to obtain information on the chalcogenide layer and the reaction layer through them.…”

Section: Introductionmentioning

confidence: 99%

Silver photodiffusion into Ge-rich amorphous germanium sulfide—neutron reflectivity study

Sakaguchi

Asaoka

Mitkova

2017

Journal of Applied Physics

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Silver diffuses into chalcogenide films upon light exposure, and the kinetics of photodiffusion has been a subject of various investigations because of the difficulties in the in situ determination of the time-dependent Ag reaction and diffusion development in the chalcogenide layers. In this paper, we report the results of time-resolved neutron reflectivity measurement of Ag/Ge 40 S 60 /Si substrates under light exposure to clarify the kinetics of Ag photodiffusion into Ge-rich Ge chalcogenides. It reveals that Ag ions diffuse all over the Ge chalcogenide host layer once Ag dissolves into the layer without forming a metastable reaction layer unlike the case of S-rich Ge chalcogenide such as Ge 20 S 80. The decay curve suggests that the Ag dissolution is determined by two types of Ag capturing chalcogen sites. Also, the observed relaxation time showed anomalous chalcogenide layer thickness dependence. This is attributed to an additional diffusion-driven accelerating factor, which is unique to the silver photodiffusion. Furthermore, we observed indicative changes in the formation of an inhomogeneous in-plane structure at the Ag/chalcogenide interface. This would be related to the nucleation and growth of the Ag-dissolved reaction product.

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“…The light-induced solid-state chemical reaction between various metals (Ag, Cu, Zn and Cd), and chalcogenide glasses (also known as 'photodiffusion', 'photodoping' or 'photodissolution'), has been widely studied [1][2][3][4][5][6]. However, at present, the mechanism for this photo-induced phenomenon is still speculative to our knowledge.…”

Section: Introductionmentioning

confidence: 99%

Optical properties of amorphous (As0.33S0.67)100−xTex (x=0, 1, 5 and 10) chalcogenide thin films, photodoped step-by-step with silver

Márquez

González-Leal

Bernal-Oliva

et al. 2008

Journal of Non-Crystalline Solids

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The kinetics of the photo-induced solid-state chemical reaction in Ag/As₃₃S₆₇bilayers and its reaction products

Cited by 31 publications

References 22 publications

Studies of silver photodiffusion dynamics in Ag/Ge_xS_1−x(x= 0.2 and 0.4) films using neutron reflectometry

Studies of silver photodiffusion dynamics in Ag/Ge_xS_1−x(x= 0.2 and 0.4) films using neutron reflectometry

Silver photodiffusion into Ge-rich amorphous germanium sulfide—neutron reflectivity study

Optical properties of amorphous (As0.33S0.67)100−xTex (x=0, 1, 5 and 10) chalcogenide thin films, photodoped step-by-step with silver

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The kinetics of the photo-induced solid-state chemical reaction in Ag/As33S67bilayers and its reaction products

Cited by 31 publications

References 22 publications

Studies of silver photodiffusion dynamics in Ag/GexS1−x(x= 0.2 and 0.4) films using neutron reflectometry

Studies of silver photodiffusion dynamics in Ag/GexS1−x(x= 0.2 and 0.4) films using neutron reflectometry

Silver photodiffusion into Ge-rich amorphous germanium sulfide—neutron reflectivity study

Optical properties of amorphous (As0.33S0.67)100−xTex (x=0, 1, 5 and 10) chalcogenide thin films, photodoped step-by-step with silver

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The kinetics of the photo-induced solid-state chemical reaction in Ag/As₃₃S₆₇bilayers and its reaction products

Studies of silver photodiffusion dynamics in Ag/Ge_xS_1−x(x= 0.2 and 0.4) films using neutron reflectometry

Studies of silver photodiffusion dynamics in Ag/Ge_xS_1−x(x= 0.2 and 0.4) films using neutron reflectometry