| Summary: | 碩士 === 國立新竹教育大學 === 應用科學系碩士班 === 98 === In this study, epitaxial ZnO were grown on c-plane sapphire and m-plane sapphire substrate by atomic layer deposition (ALD) with diethylzinc (DEZn) and deionized water (H2O) as the precursor. This dissertation is divided into two parts. In the first part, the ZnO thin films grown on c-plane sapphire with flow-rate interruption method compared the results of traditional continuous flow process. In the secondary part, we use the new process, ALD with flow-rate interruption method to grow epitaxial non-polar ZnO thin film on m-plane sapphire.
At first, the ZnO thin film grown on c-plane sapphire with flow rate interruption method with different temperature form 25℃-200℃. The results of high resolution X-ray diffraction (HRXRD) show the growth temperature at range from 40 to 160 degree showed better crystalline quality. In additional, the Photoluminescence (PL) spectra of ZnO thin film with flow-rate interruption method also showed the enhancement of near-band-edge (NBE) intensity. The synchrotron off-normal phi-scan of ZnO (113) bragg peak showed six-fold symmetry and well align to (101) of sapphire substrate indicated that the ZnO thin film was epitaxial relationship to sapphire. Using the flow-rate interruption method not only can improved the optical quality but also grow the epitaxial ZnO film on c-plane sapphire.
In the next, we also grew ZnO epitaxial films for different ALD cycles on m-plane sapphire at growth temperature with 200 degree by ALD with flow-rate interruption method. The synchrotron results shows two-fold symmetry of ZnO (002) indicated that the ZnO is epitaxial film. The epitaxial relationship between ZnO and sapphire follows [002]ZnO//[020]sapphire and [020]ZnO//[006]sapphire. The high resolution transmission electron microscope (HRTEM) and XRD showed that relatively minor phase is from the interface between film and substrate. The photoluminescence intensity increased with increasing crystalline quality and thickness of ZnO films.
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