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Effect of growth temperature on the characteristics of ZnO films grown on Si(111) substrates by metal-organic chemical vapor deposition
|Junjie Zhu 1, Andrej Kuznetsov 1, Inhwan Lee 2, Ran Yao 3, Zhuxi Fu 3|
1. University of Oslo, Physics Department and Centre for Materials Science and Nanotechnology, N-0316 Oslo, Blindern, Oslo N-0316, Norway
ZnO is a wide band gap semiconductor with Eg=3.36 eV at room temperature. Since the report on the stimulated emission from ZnO films was published in 1997, ZnO has attracted more and more attention. In order to fabricate the ZnO based optoelectronic devices, high quality ZnO films are necessary. In addition, for the large-scale production, the research on the metal-organic chemical vapor deposition (MOCVD) growth of high quality ZnO films is also very important.
Diethylzinc (DEZ) and O2 or H2O are normally used as the precursors for the MOCVD growth of ZnO films. However, in this the reactions are so fast that the gas line should be designed more carefully in order to prevent the pre-reaction. Therefore, we used the DEZ and CO2 as precursors to grow ZnO, in which the reaction is mild.The ZnO films were grown on Si(111) substrates by MOCVD with DEZ and CO2 as the precursors. The effects of the growth temperature on the growth rate, surface morphology, structure and optical properties of the ZnO films were investigated. The temperature window was found between 450 oC and 700 oC. In this region, with the increase of growth temperature, the growth mode was changed from kinetics limited to mass transfer limited and finally terminated as desorption limited. In addition, the ZnO crystalline gains were increased, resulting in the improvement of structure and optical property. Moveover, the rougher surface at high growth temperature also increased the PL intensity.Using CO2 as oxygen source, the optimal growth temperature was found to be near 600 oC.
Presentation: Poster at E-MRS Fall Meeting 2007, Acta Materialia Gold Medal Workshop, by Junjie Zhu
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-13 11:14 Revised: 2009-06-07 00:44