Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5361568 | Applied Surface Science | 2008 | 5 Pages |
Abstract
N-doped p-type ZnO (p â¼Â 1018cm-3) was grown on sapphire(0 0 0 1) substrate by metal-organic chemical vapor deposition method. Ni/Au metal was evaporated on the ZnO film to form contacts. As-deposited contacts were rectifying while ohmic behavior was achieved after thermally annealing the contacts in nitrogen environment. Specific contact resistance was determined by circular transmission line method and a minimum specific contact resistance of 8 Ã 10â4 Ω cm2 was obtained for the sample annealed at 650 °C for 30 s. However, Hall effect measurements indicate that, as the rapid thermal annealing temperature increased up to 550 °C or higher the samples' conductive type have changed from p-type to n-type, which may be due to the instability nature of the present-day p-type N-doped ZnO or the dissociation of ZnO caused by annealing process in N2 ambient. Evolution of the sample's electric characteristics and the increment of metal/semiconductor interface states induced by rapid thermal annealing process are supposed to be responsible for the improvement of electrical properties of Au/Ni/ZnO.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Z.P. Shan, S.L. Gu, S.M. Zhu, W. Liu, K. Tang, H. Chen, J.G. Liu, Y.D. Zheng,