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Title: Effects of AlO[sub x]-cap layer on the luminescence and photoconductivity of ZnO thin films
Authors: Hui, K. C.
Ong, H. C.
Lee, Pui-fai
Dai, Jiyan
Subjects: Zinc compounds
Aluminium compounds
II-VI semiconductors
Wide band gap semiconductors
Semiconductor thin films
Surface states
Energy gap
Deep levels
Issue Date: 11-Apr-2005
Publisher: American Institute of Physics
Source: Applied physics letters, 11 Apr. 2005, v. 86, no. 15, 152116, p. 1-3
Abstract: The effects of AlO[sub x]-cap layer on the optical and photoelectrical properties of ZnO films have been studied by cathodoluminescence (CL), photoluminescence (PL), and photoconductivity (PC). Both the PL and CL show that the cap layer improves the emission characteristics of ZnO by enhancing the band-edge emission while at the same time reducing the deep-level emissions. To study the origin of improvement, depth-resolved CL has been carried out to map out the emissions at different depths. It shows that the improvement occurs primarily at the film surface, which indicates the cap layer acts as a passivation layer that suppresses the detrimental surface states. The PC measurement on the capped ZnO at room temperature shows a distinctive excitonic feature at 3.29 eV and an overall increment of photoresponse above the band gap. Therefore, our results suggest a higher sensitivity of UV detection can be achieved in ZnO simply be employing a thin AlO[sub x]-cap layer.
Rights: © 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in K. C. Hui et al., Appl. Phys. Lett. 86, 152116 (2005) and may be found at
Type: Journal/Magazine Article
DOI: 10.1063/1.1900945
ISSN: 0003-6951 (print)
1077-3118 (online)
Appears in Collections:AP Journal/Magazine Articles

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