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Excitation Light Energy Dependence of Silver Photodiffusion into Amorphous Germanium Sulfide: Neutron and X‐Ray Reflectivity and X‐Ray Diffraction
Author(s) -
Sakaguchi Yoshifumi,
Hanashima Takayasu,
Ahmed Simon Al-Amin,
Mitkova Maria
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000178
Subject(s) - chalcogenide , germanium , materials science , amorphous solid , antibonding molecular orbital , band gap , optoelectronics , substrate (aquarium) , optics , crystallography , electron , atomic orbital , chemistry , silicon , physics , oceanography , quantum mechanics , geology
Silver photodiffusion into amorphous chalcogenides is the photoinduced phenomenon, in which mobile Ag ions are injected into semiconductor films, and is applicable to nonvolatile memory devices. To understand the role of light illumination in the silver diffusion into a chalcogenide layer, the excitation light energy dependence of silver photodiffusion in Ag/a‐Ge 20 S 80 /Si substrate stacks is investigated by neutron reflectivity, X‐ray reflectivity, and X‐ray diffraction. The measurements reveal that there is an energy threshold to induce silver photodiffusion, which corresponds to the optical gap of amorphous Ge 20 S 80 . The excitation of the lone‐pair electrons to the antibonding states by the light illumination with greater energy than the optical gap leads to the bond breaking, and the Ge–S network structure is reorganized involving Ag ions.