Disorder induced violet/blue luminescence in rf‐deposited ZnO films. Issue 4 (11th March 2013)

• Record Type: Journal Article
• Authors: Peres, M.; Magalhães, S.; Soares, M. R.; Soares, M. J.; Rino, L.; Alves, E.; Lorenz, K.; Correia, M. R.; Lourenço, A. C.; Monteiro, T.
• Is Part Of: Physica status solidi. Volume 10:Issue 4(2013:Apr.)
• Page Start: 662
• Page End: 666
• Publication Date: 2013-03-11
• Subjects: Solid state physics -- Congresses; Solid state physics -- Periodicals; Solid state physics; Conference proceedings; Periodicals; 530.41
• DOI: 10.1002/pssc.201200873
• Languages: English
• ISSNs: 1862-6351

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>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 <italic>a</italic> ‐oriented ZnO/MgO while for the <italic>c</italic> ‐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. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)</p> </abstract>