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Mechanism of excitation and relaxation in Er,O‐codoped GaAs for 1.5 μm light‐emitting devices with extremely stable wavelength
Author(s) -
Fujiwara Yasufumi,
Takemoto Shouichi,
Tokuno Takehiro,
Hidaka Keiji,
Ichida Hideki,
Suzuki Masato,
Terai Yoshikazu,
Kanematsu Yasuo,
Tonouchi Masayoshi
Publication year - 2008
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.200776702
Subject(s) - excitation , ion , excitation wavelength , wavelength , relaxation (psychology) , chemistry , electron , band gap , reflection (computer programming) , energy transfer , materials science , atomic physics , analytical chemistry (journal) , optoelectronics , molecular physics , physics , psychology , social psychology , organic chemistry , quantum mechanics , computer science , programming language , chromatography
Energy‐transfer processes in Er,O‐codoped GaAs (GaAs:Er,O) have been investigated by means of a pump and probe reflection technique. Time‐resolved reflectivity exhibited a characteristic dip; a negative signal due to bandgap renormalization in less than 1 ps and then a gradual recovery. In the recovery process, there were two components, fast and slow. The fast recovery time (several ps) was inversely proportional to Er concentration. The analysis based on a rate equation indicated that it is due to the capture of electrons by charged traps. The slow recovery (30–60 ps) was well coincident with the time (54 ps) predicted theoretically in the framework of a multiphonon‐assisted model. Optical excitation cross section of Er ions in GaAs:Er,O has also been studied in various samples and shown to depend strongly on Er concentration. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)