In this project, nano-sized gallium oxide and indium oxide produced by ion implantation of nitrogen/carbon and subsequent rapid thermal annealing (RTA) have been investigated. The material synthesis technique is based on using implantation of different species, which include nitrogen, carbon, oxygen and argon, with variable implant dosage to form an amorphous surface layer on GaAs or InP substrates. RTA then provides the required thermal energy for the amorphous material to re-crystallize. We found that the type of implanted species play an important role in controlling the material for nation during the RTA stage. Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were conducted to provide detailed characterization on the samples. For the nitrogen/carbon implanted samples, RTA at 950°C resulted in the formation of single crystalline Ga2O3 nano-ribbons on the sample surface. These Ga2O3 ribbons possess strong visible photoluminescence and cathodoluminescence. For the carbon implanted InP samples, In2O3 nanowires were found on the InP sample surface when RTA was performed at 750°C. However, In2O 3 nanowires only occurred when gold was present. On the other hand, when the nitrogen implanted samples were annealed in pure nitrogen ambient, a Raman peak at 577cm-1 associated with GaN was observed. Cross-sectional TEM showed that the thickness of the region containing GaN was about 40nm. We also used the synthesized GaN as a buffer layer to grow ZnO film by using MOCVD. The possible formation mechanisms of these nanomaterials and the role of the implanted species are discussed. For the nanowires with gold nano-particles at the free end, we believe that they are synthesized by vapour-liquid-solid (VLS) mechanism. On the other hand, the growth of nano-wires in the cases where no gold nano-particles on the free end may be explained on the basis of a vapour-solid (VS) mechanism. For the case of carbon or nitrogen implantation, carbon works as a reduction agent and nitrogen favours the formation of group III nitride template, which may lead of the growth of nano-wires. / Lo, Kwong Chun. / "March 2008." / Adviser: Aaron H. P. Ho. / Source: Dissertation Abstracts International, Volume: 70-03, Section: B, page: 1887. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (p. 112-119). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

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