| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系研究所 === 98 === Cu2O , a p-type semiconductor, which has high absorption coefficient in visible regions, has potential in solar cells applications. Since n-type doping is difficult to Cu2O, many researches on heterojunctions are found in order to apply Cu2O. ZnO, a well-known n-type semiconductor, seems to be a good candidate. ZnO (0001) and Cu2O (111) orientations have similar arrangements with lattice mismatch calculated to be 7.1%.
The Cu2O thin films were deposited by pulsed laser deposition on the ZnO, and discussing the characteristics of Cu2O thin films with series of parameters. The Nd:YAG Q-switched laser with 266nm wavelength was used for ablation. First, ZnO buffer layers with thickness about 15nm were deposited on C-sapphire substrates. The ZnO targets were made by pressed ZnO sintered under high temperature. Then, Cu2O thin films were grown on the ZnO buffer layers. The Cu2O targets were made by pressed CuO pellet which was sintered under high temperature and oxygen-free condition.
Due to the experiment results, single phase Cu2O crystals were deposited on ZnO along the expected (111) orientation. The absorption band gap, defined by absorption coefficient which was obtained trough transforming the transmittance, was 2.45eV.
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