本論文主要是研究偏壓與自供電(self-powered)氧化亞銅/氧化鋅異質接面光檢測器之特性。首先，將ITO透明導電玻璃基板浸入硫酸銅水溶液中，以電化學沉積法置備氧化亞銅薄膜，再濺鍍氧化鋅晶種層於氧化亞銅薄膜上，接著使用化學水浴沉積法合成氧化鋅奈米柱陣列，最後在氧化鋅奈米柱陣列上濺鍍鉑電極，完成氧化亞銅/氧化鋅異質接面光檢測器。本實驗透過X光繞射光譜儀(XRD)、半導體元件參數分析儀、場發射掃描式電子顯微鏡(SEM)、紫外可視近紅外分光光譜儀對光檢測器各層薄膜進行表面形貌、晶體結構、薄膜分析之探討。
接著，量測與分析不同厚度之氧化亞銅薄膜對於氧化亞銅/氧化鋅異質接面光檢測器特性之影響。氧化亞銅厚度為600 nm及350 nm所構成之光檢測器在照射450 nm波長之可見光及自供電條件下光/暗電流比分別為2.44與51.94，此結果可以歸功於氧化亞銅厚度變薄能確保450 nm波長之可見光所激發之電子電洞對能夠以較短路徑傳輸至外部電極進行有效收集。接著在照射370 nm波長之紫外光下，量測氧化亞銅厚度為350 nm所構成之光檢測器在逆向偏壓1 V與自供電時之響應速度，其上升時間分別為70.5 s與69 ms，下降時間分別為901 s與17.82 ms，此顯著之響應速度改善可歸功於在自供電時氧化鋅奈米柱陣列所產生之光電流不受表面氧吸附效應所影響。
本研究之元件具有低成本、低溫製程、低耗能、響應速度快、製程簡易、可大量製作之優點，因此它很有潛力作為光檢測器。

In this thesis, we investigated the performance of voltage-biased and self-powered operation of the p-Cu2O/n-ZnO nanorod arrays heterojunction photodetectors. First, polycrystalline p-Cu2O thin film was electrodeposited onto an indium tin oxide glass substrate. Then we sputtered a ZnO seed layer onto the pre-defined Cu2O thin film. Subsequently, ZnO nanorod arrays were synthesized by chemical bath deposition method. Finally, a Platinum film was sputtered on the ZnO nanorod arrays as the top electrode. Film’s quality and surface morphologies were analyzed by X-ray diffractometer, scanning electron microscope and UV-VIS-NIR spectrophotometer.
Under 450 nm visible light illumination and at zero bias, the photo/dark current ratio of the p-Cu2O(600nm)/n-ZnO and p-Cu2O(350nm)/n-ZnO photodetectors are 2.44 and 51.94, respectively. This result can credit to the reduced Cu2O film thickness, which let the electron-hole pairs, excited by 450 nm visible light, transport in a shorter path and can be collected by electrodes effectively. Under 370 nm UV light illumination, the rise time of the p-Cu2O(350nm)/n-ZnO photodetectors at reversed bias of 1 V and zero bias are 70.5 s and 69 ms, and the fall time are 901 s and 17.82 ms, respectively. This response time improvement is attributed to the photocurrent generated in ZnO nanorod arrays is not affected by the oxygen absorption/desorption effect under the self-powered operation.
The studied photodetector has advantages of low-cost, low-temperature processing, low power consumption, capable of self-power, simple to produce, and suitable for mass production. Thus, the photodetector has a great potential for the applications of photodetecting devices.

[1] L. Peng, L. Hu, and X. Fang, "Low‐dimensional nanostructure ultraviolet photodetectors," Advanced Materials, vol. 25, pp. 5321-5328, 2013.
[2] T. Zhai, X. Fang, M. Liao, X. Xu, H. Zeng, B. Yoshio, et al., "A comprehensive review of one-dimensional metal-oxide nanostructure photodetectors," Sensors, vol. 9, pp. 6504-6529, 2009.
[3] O. Game, U. Singh, T. Kumari, A. Banpurkar, and S. Ogale, "ZnO (N)–Spiro-MeOTAD hybrid photodiode: an efficient self-powered fast-response UV (visible) photosensor," Nanoscale, vol. 6, pp. 503-513, 2014.
[4] X. Li, C. Gao, H. Duan, B. Lu, Y. Wang, L. Chen, et al., "High‐Performance Photoelectrochemical‐Type Self‐Powered UV Photodetector Using Epitaxial TiO2/SnO2 Branched Heterojunction Nanostructure," Small, vol. 9, pp. 2005-2011, 2013.
[5] G. Konstantatos and E. H. Sargent, "Nanostructured materials for photon detection," Nature Nanotechnology, vol. 5, p. 391, 2010.
[6] O. Lupan, L. Chow, G. Chai, L. Chernyak, O. Lopatiuk‐Tirpak, and H. Heinrich, "Focused‐ion‐beam fabrication of ZnO nanorod‐based UV photodetector using the in‐situ lift‐out technique," physica Status Solidi (a), vol. 205, pp. 2673-2678, 2008.
[7] M. Liao, Y. Koide, and J. Alvarez, "Thermally stable visible-blind diamond photodiode using tungsten carbide Schottky contact," Applied Physics Letters, vol. 87, p. 022105, 2005.
[8] L. Östlund, Q. Wang, R. Esteve, S. Almqvist, D. Rihtnesberg, S. Reshanov, et al., "4H‐and 6H‐SiC UV photodetectors," Physica Status Solidi (c), vol. 9, pp. 1680-1682, 2012.
[9] D. Walker, E. Monroy, P. Kung, J. Wu, M. Hamilton, F. Sanchez, et al., "High-speed, low-noise metal–semiconductor–metal ultraviolet photodetectors based on GaN," Applied Physics Letters, vol. 74, pp. 762-764, 1999.
[10] F. Guo, B. Yang, Y. Yuan, Z. Xiao, Q. Dong, Y. Bi, et al., "A nanocomposite ultraviolet photodetector based on interfacial trap-controlled charge injection," Nature Nanotechnology, vol. 7, p. 798, 2012.
[11] Y.-Y. Lin, C.-W. Chen, W.-C. Yen, W.-F. Su, C.-H. Ku, and J.-J. Wu, "Near-ultraviolet photodetector based on hybrid polymer/zinc oxide nanorods by low-temperature solution processes," Applied Physics Letters, vol. 92, p. 205, 2008.
[12] S. M. Hatch, J. Briscoe, and S. Dunn, "A Self‐Powered ZnO‐Nanorod/CuSCN UV Photodetector Exhibiting Rapid Response," Advanced Materials, vol. 25, pp. 867-871, 2013.
[13] Y. Xie, H. Huang, W. Yang, and Z. Wu, "Low dark current metal-semiconductor-metal ultraviolet photodetectors based on sol-gel-derived TiO2 films," Journal of Applied Physics, vol. 109, p. 023114, 2011.
[14] Y. Kokubun, K. Miura, F. Endo, and S. Nakagomi, "Sol-gel prepared β-Ga2O3 thin films for ultraviolet photodetectors," Applied Physics Letters, vol. 90, p. 031912, 2007.
[15] H. Chen, L. Hu, X. Fang, and L. Wu, "General Fabrication of Monolayer SnO2 Nanonets for High‐Performance Ultraviolet Photodetectors," Advanced Functional Materials, vol. 22, pp. 1229-1235, 2012.
[16] B. J. Hansen, Y. Liu, R. Yang, and Z. L. Wang, "Hybrid nanogenerator for concurrently harvesting biomechanical and biochemical energy," ACS Nano, vol. 4, pp. 3647-3652, 2010.
[17] Y. Q. Bie, Z. M. Liao, H. Z. Zhang, G. R. Li, Y. Ye, Y. B. Zhou, et al., "Self‐Powered, ultrafast, visible‐blind UV detection and optical logical operation based on ZnO/GaN Nanoscale p‐n junctions," Advanced Materials, vol. 23, pp. 649-653, 2011.
[18] D. Wu, Y. Jiang, Y. Zhang, Y. Yu, Z. Zhu, X. Lan, et al., "Self-powered and fast-speed photodetectors based on CdS:Ga nanoribbon/Au Schottky diodes," Journal of Materials Chemistry, vol. 22, pp. 23272-23276, 2012.
[19] X. Fang, Y. Bando, M. Liao, T. Zhai, U. K. Gautam, L. Li, et al., "An efficient way to assemble ZnS nanobelts as ultraviolet‐light sensors with enhanced photocurrent and stability," Advanced Functional Materials, vol. 20, pp. 500-508, 2010.
[20] Z. Gao, W. Jin, Y. Zhou, Y. Dai, B. Yu, C. Liu, et al., "Self-powered flexible and transparent photovoltaic detectors based on CdSe nanobelt/graphene Schottky junctions," Nanoscale, vol. 5, pp. 5576-5581, 2013.
[21] T. Zhai, X. Fang, M. Liao, X. Xu, L. Li, B. Liu, et al., "Fabrication of high-quality In2Se3 nanowire arrays toward high-performance visible-light photodetectors," ACS Nano, vol. 4, pp. 1596-1602, 2010.
[22] K. Chen, C. Sun, S. Song, and D. Xue, "Polymorphic crystallization of Cu2O compound," CrystEngComm, vol. 16, pp. 5257-5267, 2014.
[23] K. Fujimoto, T. Oku, and T. Akiyama, "Fabrication and characterization of ZnO/Cu2O solar cells prepared by electrodeposition," Applied Physics Express, vol. 6, p. 086503, 2013.
[24] A. Musa, T. Akomolafe, and M. Carter, "Production of cuprous oxide, a solar cell material, by thermal oxidation and a study of its physical and electrical properties," Solar Energy Materials and Solar Cells, vol. 51, pp. 305-316, 1998.
[25] J. Deuermeier, J. Gassmann, J. Brötz, and A. Klein, "Reactive magnetron sputtering of Cu2O: Dependence on oxygen pressure and interface formation with indium tin oxide," Journal of Applied Physics, vol. 109, p. 113704, 2011.
[26] J. Lee and Y. Tak, "Epitaxial Growth of Cu2O (111) by Electrodeposition," Electrochemical and Solid-State Letters, vol. 2, pp. 559-560, 1999.
[27] Q. Hua, D. Shang, W. Zhang, K. Chen, S. Chang, Y. Ma, et al., "Morphological evolution of Cu2O nanocrystals in an acid solution: stability of different crystal planes," Langmuir, vol. 27, pp. 665-671, 2010.
[28] K. Chen, C. Sun, and D. Xue, "Morphology engineering of high performance binary oxide electrodes," Physical Chemistry Chemical Physics, vol. 17, pp. 732-750, 2015.
[29] S. Ishizuka, S. Kato, Y. Okamoto, and K. Akimoto, "Hydrogen treatment for polycrystalline nitrogen-doped Cu2O thin film," Journal of Crystal Growth, vol. 237, pp. 616-620, 2002.
[30] X. Zhao, P. Wang, and B. Li, "CuO/ZnO core/shell heterostructure nanowire arrays: synthesis, optical property, and energy application," Chemical Communications, vol. 46, pp. 6768-6770, 2010.
[31] H. J. Bolink, E. Coronado, D. Repetto, and M. Sessolo, "Air stable hybrid organic-inorganic light emitting diodes using ZnO as the cathode," Applied Physics Letters, vol. 91, p. 223501, 2007.
[32] C. Fan, Q. Wang, L. Li, S. Zhang, Y. Zhu, X. Zhang, et al., "Bulk moduli of wurtzite, zinc-blende, and rocksalt phases of ZnO from chemical bond method and density functional theory," Applied Physics Letters, vol. 92, p. 101917, 2008.
[33] K. Akimoto, S. Ishizuka, M. Yanagita, Y. Nawa, G. K. Paul, and T. Sakurai, "Thin film deposition of Cu2O and application for solar cells," Solar Energy, vol. 80, pp. 715-722, 2006.
[34] S. Pearton, D. Norton, K. Ip, Y. Heo, and T. Steiner, "Recent progress in processing and properties of ZnO," Progress in Materials Science, vol. 50, pp. 293-340, 2005.
[35] B. Cao and W. Cai, "From ZnO nanorods to nanoplates: chemical bath deposition growth and surface-related emissions," The Journal of Physical Chemistry C, vol. 112, pp. 680-685, 2008.
[36] C. Soci, A. Zhang, B. Xiang, S. A. Dayeh, D. Aplin, J. Park, et al., "ZnO nanowire UV photodetectors with high internal gain," Nano Letters, vol. 7, pp. 1003-1009, 2007.
[37] G. Du, W. Liu, J. Bian, L. Hu, H. Liang, X. Wang, et al., "Room temperature defect related electroluminescence from ZnO homojunctions grown by ultrasonic spray pyrolysis," Applied Physics Letters, vol. 89, p. 052113, 2006.
[38] F.-Y. Shih, Y.-C. Wu, Y.-S. Shih, M.-C. Shih, T.-S. Wu, P.-H. Ho, et al., "Environment-insensitive and gate-controllable photocurrent enabled by bandgap engineering of MoS2 junctions," Scientific Reports, vol. 7, p. 44768, 2017.
[39] K. Musselman, Y. Ievskaya, and J. MacManus-Driscoll, "Modelling charge transport lengths in heterojunction solar cells," Applied Physics Letters, vol. 101, p. 253503, 2012.
[40] S. M. Sze and K. K. Ng, Physics of Semiconductor Devices: John wiley & sons, 2006.
[41] A. J. Bard, L. R. Faulkner, J. Leddy, and C. G. Zoski, Electrochemical Methods: Fundamentals and Applications vol. 2: wiley New York, 1980.
[42] Q. Li, J. Bian, J. Sun, J. Wang, Y. Luo, K. Sun, et al., "Controllable growth of well-aligned ZnO nanorod arrays by low-temperature wet chemical bath deposition method," Applied Surface Science, vol. 256, pp. 1698-1702, 2010.
[43] S. Roy, N. Banerjee, C. Sarkar, and P. Bhattacharyya, "Development of an ethanol sensor based on CBD grown ZnO nanorods," Solid-State Electronics, vol. 87, pp. 43-50, 2013.
[44] L. Schmidt-Mende and J. L. MacManus-Driscoll, "ZnO–nanostructures, defects, and devices," Materials today, vol. 10, pp. 40-48, 2007.
[45] H.-P. Lin, X.-J. Lin, and D.-C. Perng, "Electrodeposited CuSCN metal-semiconductor-metal high performance deep-ultraviolet photodetector," Applied Physics Letters, vol. 112, p. 021107, 2018.