| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 101 === In this study, Mg2TiO4 thin films were deposited on p-type Si(111) substrate by the sol-gel process. Firstly, the Mg2TiO4 thin films’ structural, optical and electrical properties were characterized at different annealing temperatures using x-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), conductivity measurements and photoluminescence (PL). Experimental results indicate that the Mg2TiO4 thin films crystallized at the annealing temperature of 800℃, and the interface between the thin films and substrate began diffusing at an annealing temperature of 900℃. The interface diffusion apparently influenced the thin films’ structural, optical and electrical properties Hence, we obtained the best properties at an 800℃annealing temperature, at which point the leakage current was 10-7J(A/cm2)~10-8J(A/cm2), the dielectric constant was approximately 12, and the photoluminescence had a strong intensity at the 700nm-750nm wavelength.
Secondly, we introduced different atmospheres (Air、O2、N2、N2/H2、vacuum) when annealing, and then compared the influence of these atmospheres on photoluminescence. It was found that the O2 atmosphere had the strongest intensity, while the N2/H2 atmosphere had the weakest. Consequently, we suspect that the oxygen vacancy may suppress Mg2TiO4 thin film photoluminescence intensity. Ultimately, we found that choosing an appropriate crystallizing and annealing temperature in an O2 atmosphere can achieve strong photoluminescence intensity for Mg2TiO4thin films.
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