| Summary: | 碩士 === 大葉大學 === 電機工程學系 === 102 === In this study, the ZnO p-n junctions were fabricated on Si (0 0 1) substrates by the rf magnetron sputtering system to investigate the electrical and optical properties. In the first phase, ZnO thin films were fabricated on Si (0 0 1) substrates with various nitrogen volume percentage at different temperature (room temperature, 200 C, 300 C, and 400 C), where nitrogen was introduced to the growth chamber as the p-type dopant source. During the growth of the films, the reactive gas nitrogen was firstly introduced to the chamber with different pressure, and then the working gas argon flew in to keep the total pressure at 40 mTorr. The X-ray diffraction data showed the [0 0 1] direction of the ZnO:N films is perpendicular to the substrate surface. To characterize the deposited thin films, resistivity, carrier concentration, and carrier mobility were measured by the Hall measurement system. The ZnO:N thins films grown at high-temperature show a positive sign of the Hall coefficient confirmed that the p-type conductivity.
In the second phase, a photoresist was coating on the previously prepared p-type ZnO:N films surface. Next, an exposure and development process was performed to define the passivation region on the photoresist layer. Then, the resist pattern was transferred into ZnO:N via wet etching. The second ZnO layer was patterned by lift-off method. A sacrificial photoresist layer was first deposited on the patterned p-type ZnO, then the inverse pattern was created via exposure and development. After the n-type ZnO thin film was fabricated over the whole area, the sacrificial was washed away by acetone to reveal the desired pattern. The I-V characteristics, hall coefficient, and photoconductivity were measured to explore the properties of the ZnO devices.
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