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A XANES Study of Cu Valency in Cu‐Doped Epitaxial ZnO
Author(s) -
Fons P.,
Nakahara K.,
Yamada A.,
Iwata K.,
Matsubara K.,
Takasu H.,
Niki S.
Publication year - 2002
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 - 10.1002/1521-3951(200201)229:2<849::aid-pssb849>3.0.co;2-o
Subject(s) - valency , xanes , valence (chemistry) , dopant , annealing (glass) , materials science , analytical chemistry (journal) , doping , copper , argon , molecular beam epitaxy , epitaxy , crystallography , chemistry , metallurgy , spectroscopy , nanotechnology , optoelectronics , physics , philosophy , linguistics , quantum mechanics , layer (electronics) , organic chemistry , chromatography
Near‐edge X‐ray absorption (XANES) at the Cu K‐edge was employed to study the valency of Cu (a potential p‐dopant) in Cu‐doped ZnO grown by molecular beam epitaxy. For a similar chemical environment, a shift in the onset of absorption can be interpreted as being due to a change in effective valency. We have studied this shift for both as‐grown and argon ambient annealed (1000 °C, 30 min) Cu‐doped ZnO samples. The valency shift was measured against ab‐initio standards calculated using feff8 as well as the standard samples Cu 2 O (+1 valence) and CuO (+2 valence). It was found for the flux region explored here that as‐incorporated Cu assumes an effective valence of approximately +1 which increases towards +2 upon a 1000 °C argon ambient anneal. X‐ray diffraction also shows the presence of both metallic Cu and Cu 2 O depending upon growth and annealing conditions.