Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1538039 | Optics Communications | 2009 | 6 Pages |
Abstract
ZnO and Al-doped ZnO(ZAO) thin films have been prepared on glass substrates by direct current (dc) magnetron sputtering from 99.99% pure Zn metallic and ZnO:3Â wt%Al2O3 ceramic targets, the effects of substrate temperature on the crystallization behavior and optical properties of the films have been studied. It shows that the surface morphologies of ZAO films exhibit difference from that of ZnO films, while their preferential crystalline growth orientation revealed by X-ray diffraction remains always the (0Â 0Â 2). The optical transmittance and photoluminescence (PL) spectra of both ZnO and ZAO films are obviously influenced by the substrate temperature. All films exhibit a transmittance higher than 86% in the visible region, while the optical transmittance of ZAO films is slightly smaller than that of ZnO films. More significantly, Al-doping leads to a larger optical band gap (Eg) of the films. It is found from the PL measurement that near-band-edge (NBE) emission and deep-level (DL) emission are observed in pure ZnO thin films. However, when Al was doped into thin films, the DL emission of the thin films is depressed. As the substrate temperature increases, the peak of NBE emission has a blueshift to region of higher photon energy, which shows a trend similar to the Eg in optical transmittance measurement.
Keywords
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Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
Xue-Yong Li, Hong-Jian Li, Zhi-Jun Wang, Hui Xia, Zhi-Yong Xiong, Jun-Xi Wang, Bing-Chu Yang,