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Kinetics of Silver Photodiffusion Into Amorphous Ge 20 S 80 Films: Case of Pre‐Reaction
Author(s) -
Sakaguchi Yoshifumi,
Hanashima Takayasu,
Aoki Hiroyuki,
Asaoka Hidehito,
Ahmed Simon AlAmin,
Mitkova Maria
Publication year - 2018
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201800049
Subject(s) - amorphous solid , kinetics , chemical engineering , chemical kinetics , materials science , chemistry , crystallography , physics , engineering , quantum mechanics
Silver photodiffusion into amorphous chalcogenide has attracted much attention because of its potential applications for example in memory devices. For its development, it is important to know how Ag ions diffuse in chalcogenide layers upon light exposure. In this paper, the photo‐induced effect on “pre‐reacted” films before light exposure, originating from Ag/Ge 20 S 80 /Si substrate and Ge 20 S 80 /Ag/Si substrate is investigated, using neutron reflectivity, X‐ray reflectivity, and X‐ray diffraction. Two types of “pre‐reacted” films according to the original stacking order are obtained. In both cases, a pure Ag layer almost disappeared, and there is a small amount of monoclinic Ag 2 S. The reaction time for the photodiffusion is shorter, in both cases, than that in Ag/Ge 20 S 80 with a pure Ag layer, indicating a different reaction process. After prolonged light exposure, a uniform amorphous reaction layer is produced in the films originating from the Ag/Ge 20 S 80 /Si substrate, while both an amorphous reaction product and the Ag 2 S fragments exist in the films originating from Ge 20 S 80 /Ag/Si substrate. The mechanism of the specific photo‐reaction is discussed in terms of the role of the Ag 2 S fragments.