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Optical absorption of EL2 0 and EL2 + in semi‐insulating GaAs: Cr
Author(s) -
Ulrici W.
Publication year - 1986
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.2221340229
Subject(s) - photoionization , absorption (acoustics) , quenching (fluorescence) , absorption spectroscopy , spectral line , analytical chemistry (journal) , materials science , atomic physics , chemistry , optics , physics , fluorescence , ionization , ion , organic chemistry , chromatography , astronomy
The analysis of the optical absorption spectra of semi‐insulating GaAs: Cr measured at T = 78 K before and after illumination with light quenching the absorption due to EL2 centres shows that besides Cr 2+ , Cr 3+ , and filled (EL2 0 ) deep‐donor centres also empty (EL2 + ) centres may be present. These EL2 + centres cause an optical absorption with spectral shape in accordance with the photoionization cross section σ p . The optical quenching of EL2 + is connected with an increase of [Cr 3+ ] by hole capturing. A procedure is proposed to evaluate [EL2 0 ], [EL2 + ], [Cr 2+ ], and [Cr 3+ ] from the optical absorption spectra.