Disorder induced violet/blue luminescence in rf-deposited ZnO films
authors Peres, M; Magalhaes, S; Soares, MR; Soares, MJ; Rino, L; Alves, E; Lorenz, K; Correia, MR; Lourenco, AC; Monteiro, T
editors Calvez, S; Rorison, J; Guina, M; Alexandropoulos, D; Balkan, N
nationality International
journal PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 10, NO 4
author keywords ZnO; blue band; defects; disorder effects
keywords PHOTOLUMINESCENCE; BLUE; SEMICONDUCTORS; GLASS; GAP
abstract In this work ZnO thin films were deposited on different substrates, glass, silicon (100), and MgO (100) using rf-magnetron sputtering at low temperature in order to promote a large defect density, aiming to study a possible correlation with the observed violet/blue emission band. The peak position, width and low energy band shape asymmetry of the violet/blue band was found to be dependent on the deposition temperature and oxygen partial pressure. The structural analysis of deposited films reveals an epitaxial relationship for the a-oriented ZnO/MgO while for the c-oriented ZnO/Si no epitaxial relation was found with the substrate. The dependence of the violet/blue band on temperature displays always a shift of the peak position to lower energies, discarding the hypothesis of a free to bound transition. The sublinear dependence of the emission intensity with the excitation intensity suggests that the violet/blue bands on both samples could have a donor-acceptor pair nature. However, the unusually strong shift of the peak position to lower energies for the ZnO/MgO films and the emphasised asymmetric band shape for the ZnO/Si samples suggest that potential fluctuations in the electronic bands, due to disorder induced charged defects, could also be considered as an alternative recombination model for the violet/blue band. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
publisher WILEY-V C H VERLAG GMBH
issn 1862-6351
year published 2013
volume 10
issue 4
beginning page 662
ending page 666
digital object identifier (doi) 10.1002/pssc.201200873
web of science category Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter
subject category Materials Science; Physics
unique article identifier WOS:000317284600026

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