| Summary: | 碩士 === 國立臺北科技大學 === 製造科技研究所 === 104 === In this study, polar and nonpolar ZnO thin film were used to be a buffer layer to synthesize the polar and nonpolar ZnO nanaorods for UV photodetector sensing layer. First, polar and nonpolar thin films were deposited onto p-Si (100) substrate using Plasma Enhanced Chemical Vapor Deposition system. Second, the two different as-prepared thin films was used to synthesize the polar and nonpolar ZnO nanaorods as buffer layer by a simple hydrothermal method. In this part we investigated the influence of different temperature, mole concentration of aqueous solution and synthesized time. As the result, we successfully synthesized the vertical polar ZnO nanorods at 90 oC, 0.05 Mole in 3 h and horizontal nonpolar ZnO nanorods at 80 oC, 0.05 Mole in 1 h. Finally, we used two different metal materials as electrode to fabricate horizontal structures of metal-semiconductor-metal (MSM) with schottky contact behavior. The interdigital Pt electrodes were preparing by sputtering and lithography techniques, and colloidal silver electrodes were directly coating onto sample, respectively. As the result, the performance of ZnO-based photodetector with interdigital Pt electrodes is better than silver electrodes, it is showing the good reproducibility and stability after 5times switching of UV illumination. Moreover, the sensitivity was enhanced after synthesized the nanorods structure on the polar/nonpolar ZnO buffer layer. For ZnO-based photodetector with polar nanorod structure, the response time decreased from 4.37 sec to 1.81 sec and the recovery time decreased to 4.87 sec. On the other hand, in the case of ZnO-based photodetector with nonpolar nanorod structure, the response time decreased from 0.141 sec to 0.125 sec and the recovery time decreased from 0.125 sec to 0.11 sec. According to the results, the nonpolar ZnO nanorods photodetector exhibit a good sensitivity with ultra-fast response and recovery time.
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