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Optical Charge Transfer Spectra and EPR Spectra of Cr 2+ (d 4 ) and Cr 1+ (d 5 ) in CdTe
Author(s) -
Cieplak M. Z.,
Godlewski M.,
Baranowski J. M.
Publication year - 1975
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.2220700133
Subject(s) - electron paramagnetic resonance , atomic physics , spectral line , ground state , absorption spectroscopy , chromium , electron , charge (physics) , valence (chemistry) , impurity , cadmium telluride photovoltaics , acceptor , chemistry , absorption (acoustics) , analytical chemistry (journal) , physics , nuclear magnetic resonance , condensed matter physics , organic chemistry , astronomy , quantum mechanics , optoelectronics , chromatography , acoustics
Abstract By EPR experiments is shown that two charge states of chromium impurity are present in CdTe:Cr. The Cr 2+ (d 4 ) state has an acceptor character and can accept an additional electron into the d‐shell. The energy required to change the charge state of Cr 2+ (d 4 ) into Cr 1+ (d 5 ) by transferring one electron from the valence band is about 1.2 to 1.3 eV. The photosensitive EPR spectrum due to Cr 1+ (d 5 ) shows that the observed intense exponential absorption tail is due to this charge transfer process. The shape of the exponential tail is also investigated. It is suggested that the exponential character of the absorption tail is due to the presence of a Jahn‐Teller effect in the ground state of Cr 2+ (d 4 ).