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Pressure behaviour of the UV and green emission bands in ZnO micro‐rods
Author(s) -
Li G. H.,
Su F. H.,
Wang W. J.,
Ding K.,
Chen W.,
Liu Y. F.,
Joly A. G.
Publication year - 2007
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.200672545
Subject(s) - exciton , phonon , band gap , ultraviolet , pressure coefficient , emission spectrum , rod , temperature coefficient , spectral line , materials science , photoluminescence , electronic band structure , chemistry , analytical chemistry (journal) , atomic physics , condensed matter physics , physics , optoelectronics , thermodynamics , medicine , chromatography , astronomy , composite material , alternative medicine , pathology
The pressure behavior of the ultraviolet (UV) and green emission bands in ZnO tetrapod‐like micro‐rods has been investigated at 300 and 70 K, respectively. The pressure coefficient of the UV band at 300 K is 24.5 meV/GPa, consistent with that of the band gap of bulk ZnO. However, the pressure coefficient of the green band is 25 meV/GPa, far larger than previous literature reports. The green band in this work originates from Cu‐related emission, as confirmed by the fine structure observed in the spectra at 10 K. The pressure coefficients of four phonon replicas of the free exciton emission (FX) at 70 K are 21.0, 20.2, 19.8, and 19.3 meV/GPa, respectively. The energy shift rate of the FX emission and the LO phonon energies is then determined to be 21.4 and 0.55 meV/GPa. The pressure coefficient of the neutral donor bound exciton (D 0 X) transition is 20.5 meV/GPa, only 4% smaller than that of FX. This confirms that the D 0 X emission corresponds to excitons bound to neutral shallow donors. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)