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Excitation relaxation in copper selenide nanowires
Author(s) -
Juška Gediminas,
Jagminas Arūnas,
Gulbinas Vidmantas
Publication year - 2009
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.200844480
Subject(s) - relaxation (psychology) , excitation , ultrafast laser spectroscopy , femtosecond , absorption (acoustics) , charge carrier , chemistry , spectroscopy , molecular physics , ultrashort pulse , absorption spectroscopy , atomic physics , zinc selenide , nanowire , materials science , optoelectronics , optics , laser , physics , psychology , social psychology , quantum mechanics , composite material
Ultrafast nonequilibrium charge carrier relaxation in highly ordered Cu 2– x Se nanowires of 8 nm, 13 nm and 25 nm diameter was investigated by means of femtosecond pump–probe absorption spectroscopy. Transient absorption bleaching was observed in the region of the near infrared absorption band, whereas an induced absorption dominated at higher energies. The transient absorption kinetics is almost independent of the excitation and probe wavelength and shows a biexpoenetial charge carrier recombination with the excitation intensity dependent decay rates. The initial ultrafast relaxation, which gets slower at higher excitation intensities, is followed by the slower decay component emerging at high intensities. These relaxation peculiarities are discussed in terms of recombination enhancement by intragap states, and relaxation kinetics is described by a theoretical model of two concurrent relaxation channels involving deep and shallow impurity levels. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)