| Summary: | 碩士 === 大同大學 === 電機工程學系(所) === 107 === In this study, the gallium telluride (GaTe) thin films are grown on sapphire(0001) by molecular beam epitaxy. The high crystal quality GaTe thin films are demonstrated by varying the molecular flow ratio of Gallium and Tellurium and the substrate temperature. Reflectance high energy electron diffraction(RHEED) is an in-situ measurement to the surface structure. The growth rate is about 125 nm/hr which is calculated by the cross sectional SEM images. In the EDS analysis, the atomic ratio of Ga and Te is about 1:1. We gradually reduce growth time to fabricate the ultra-thin films. The XRD patterns show that the crystal structure of GaTe is related to the thickness. The crystal structure of GaTe close to the interface is collaborated to hexagonal. The crystal structure transform to monoclinic when the thickness more than about 125 nm. This is the critical thickness of GaTe. The GaTe thin films were lift-off by two methods. Firstly, we used mechanical stripping by 3M tape. It is work but the thin film will break into pieces. Secondly, we creat a lateral force stripping method with hot melt adhesive. It can take off large area thin film without broken. Then transpose thin film onto copper grids and compare its optical properties. However, GaTe thin films exhibit a strong correlation to air. In order to overcome the oxidation problem, a ZnSe is grown following the GaTe thin film. In the result of Raman scattering spectra, the GaTe thin film did not oxide although the sample exposed in the air several weeks.
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