本論文主要是研究利用塗佈氧化鎳薄膜以及化學水浴法沉積一層硫化銻在ITO玻璃基板上，氧化鎳作為電洞傳輸層，取代有機電洞注入層PEDOT:PSS與寬能隙的TPD-Si2有機電洞傳輸層，接著濺鍍沉積一層氧化鋅晶種層，再利用化學水浴法沉積氧化鋅奈米柱與濺鍍沉積鋁電極，完成光檢測器。此光檢測主動層裡包含P型的氧化鎳無機材料、硫化銻及N型氧化鋅的奈米柱。當元件操作在無偏壓下，光檢測層在照射可見光(硫化銻吸收)以及紫外光之後，產生的光電子電洞會因P-N接面造成的內建電場拉開至元件兩側電極，產生光電流。
本實驗透過低掠角薄膜X光繞射光譜儀(XRD)、X射線光電子能譜儀(XPS)、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晶體結構、薄膜分析、表面形貌及光電特性做探討。
我們評估此光檢測器在照紫外光與可見光後其光電特性，也討論在負偏壓(-1V)下以及自供電時元件的光響應度。自供電下，在可見光(500 nm)的部分，其光暗電流比都有十倍以上;在紫外光(380 nm)的部分，光暗電流比能夠到百倍以上。此外本元件也分析自供電以及運作在負偏壓下的響應速度，硫化銻基本上佔據了兩側P-N中的空乏區，在自供電下，材料吸收了光產生了電子電洞對，光電流因而由擴散電流主導，相對於操作在負偏壓下，大大加快了響應速度。

This thesis studies the photo-detecting characteristics of a photodiode with an ITO/NiO/Sb2S3/ZnO nanorods structure. NiO film is used as a hole transport layer to replace the organic hole injection layer PEDOT:PSS and TPD-Si2.
First, the inorganic NiO was deposited using a spin-coating method and the Sb2S3 film was deposited by chemical bath deposition (CBD) method. Then, a ZnO seed layer was deposited by sputtering followed by ZnO nanorods deposition using CBD. Finally, the Al electrode was deposited by DC-sputtering with a shadow mask.
Film’s quality and surface morphologies were analyzed by X-ray diffractometer, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and UV-VIS-NIR spectrophotometer was used for characterizing its optoelectronic properties.
This device’s photo response under negative and no bias (or self-powered) was evaluated. Under visible light (500 nm) illumination, the ratio of photo- to dark- current is more than one order of magnitude; With ultraviolet light (380 nm) illumination, the ratio of photo- to dark- current is more than 2 orders of magnitude. This device also analyzes the response speed without bias and under negative bias. Sb2S3 film is located in between the depletion region of the P-N layers. When device operates under zero bias, materials absorb light and generate electron-hole pairs which the photo-generated current is dominated by the diffusion current, which greatly improves the response speed as compare to device which operates under negative bias.

[1] M. Razeghi and A. Rogalski, "Semiconductor ultraviolet detectors," Journal of Applied Physics, vol. 79, pp. 7433-7473, 1996.
[2] O. Torres, A. Tanskanen, B. Veihelmann, C. Ahn, R. Braak, P. K. Bhartia, et al., "Aerosols and surface UV products from Ozone Monitoring Instrument observations: An overview," Journal of Geophysical Research: Atmospheres, vol. 112, 2007.
[3] H. Kind, H. Yan, B. Messer, M. Law, and P. Yang, "Nanowire ultraviolet photodetectors and optical switches," Advanced Materials, vol. 14, p. 158, 2002.
[4] K. Roy, M. Padmanabhan, S. Goswami, T. P. Sai, G. Ramalingam, S. Raghavan, et al., "Graphene–MoS2 hybrid structures for multifunctional photoresponsive memory devices," Nature Nanotechnology, vol. 8, p. 826, 2013.
[5] H. Melchior, M. B. Fisher, and F. R. Arams, "Photodetectors for optical communication systems," Proceedings of the IEEE, vol. 58, pp. 1466-1486, 1970.
[6] A. Sobhani, M. W. Knight, Y. Wang, B. Zheng, N. S. King, L. V. Brown, et al., "Narrowband photodetection in the near-infrared with a plasmon-induced hot electron device," Nature Communications, vol. 4, p. 1643, 2013.
[7] J. Kong, N. R. Franklin, C. Zhou, M. G. Chapline, S. Peng, K. Cho, et al., "Nanotube molecular wires as chemical sensors," Science, vol. 287, pp. 622-625, 2000.
[8] R. Martel, T. Schmidt, H. Shea, T. Hertel, and P. Avouris, "Single-and multi-wall carbon nanotube field-effect transistors," Applied Physics Letters, vol. 73, pp. 2447-2449, 1998.
[9] M.-S. White, D. Olson, S. Shaheen, N. Kopidakis, and D. S. Ginley, "Inverted bulk-heterojunction organic photovoltaic device using a solution-derived ZnO underlayer," Applied Physics Letters, vol. 89, p. 143517, 2006.
[10] M.-P. Lu, J. Song, M.-Y. Lu, M.-T. Chen, Y. Gao, L.-J. Chen, et al., "Piezoelectric nanogenerator using p-type ZnO nanowire arrays," Nano Letters, vol. 9, pp. 1223-1227, 2009.
[11] L. B. Luo, J. J. Chen, M. Z. Wang, H. Hu, C. Y. Wu, Q. Li, et al., "Near‐Infrared Light Photovoltaic Detector Based on GaAs Nanocone Array/Monolayer Graphene Schottky Junction," Advanced Functional Materials, vol. 24, pp. 2794-2800, 2014.
[12] X. Chen, K. Liu, Z. Zhang, C. Wang, B. Li, H. Zhao, et al., "Self-powered solar-blind photodetector with fast response based on Au/β-Ga2O3 nanowires array film schottky junction," ACS Applied Materials & Interfaces, vol. 8, pp. 4185-4191, 2016.
[13] 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.
[14] 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.
[15] G. Chen, B. Liang, X. Liu, Z. Liu, G. Yu, X. Xie, et al., "High-performance hybrid phenyl-C61-butyric acid methylester/Cd3P2 nanowire ultraviolet–visible–near infrared photodetectors," ACS nano, vol. 8, pp. 787-796, 2013.
[16] 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.
[17] R. Debnath, T. Xie, B. Wen, W. Li, J. Y. Ha, N. F. Sullivan, et al., "A solution-processed high-efficiency p-NiO/n-ZnO heterojunction photodetector," RSC Advances, vol. 5, pp. 14646-14652, 2015.
[18] Ü. Özgür, Y. I. Alivov, C. Liu, A. Teke, M. Reshchikov, S. Doğan, et al., "A comprehensive review of ZnO materials and devices," Journal of Applied Physics, vol. 98, p. 11, 2005.
[19] R. Vogel, P. Hoyer, and H. Weller, "Quantum-sized PbS, CdS, Ag2S, Sb2S3, and Bi2S3 particles as sensitizers for various nanoporous wide-bandgap semiconductors," The Journal of Physical Chemistry, vol. 98, pp. 3183-3188, 1994.
[20] C.-T. Sah, R. N. Noyce, and W. Shockley, "Carrier generation and recombination in pn junctions and pn junction characteristics," Proceedings of the IRE, vol. 45, pp. 1228-1243, 1957.
[21] A. Kongkanand, K. Tvrdy, K. Takechi, M. Kuno, and P. V. Kamat, "Quantum dot solar cells. Tuning photoresponse through size and shape control of CdSe− TiO2 architecture," Journal of the American Chemical Society, vol. 130, pp. 4007-4015, 2008.
[22] T. Lin, X. Li, and J. Jang, "High performance p-type NiOx thin-film transistor by Sn doping," Applied Physics Letters, vol. 108, p. 233503, 2016.
[23] A. Liu, G. Liu, H. Zhu, B. Shin, E. Fortunato, R. Martins, et al., "Hole mobility modulation of solution-processed nickel oxide thin-film transistor based on high-k dielectric," Applied Physics Letters, vol. 108, p. 233506, 2016.
[24] J. You, L. Meng, T.-B. Song, T.-F. Guo, Y. M. Yang, W.-H. Chang, et al., "Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers," Nature Nanotechnology, vol. 11, p. 75, 2016.
[25] H. Zhang, J. Cheng, F. Lin, H. He, J. Mao, K. S. Wong, et al., "Pinhole-free and surface-nanostructured NiOx film by room-temperature solution process for high-performance flexible perovskite solar cells with good stability and reproducibility," ACS Nano, vol. 10, pp. 1503-1511, 2015.
[26] I. Hotový, D. Buc, Š. Haščík, and O. Nennewitz, "Characterization of NiO thin films deposited by reactive sputtering," Vacuum, vol. 50, pp. 41-44, 1998.
[27] D. Adler and J. Feinleib, "Band structure of magnetic semiconductors," Journal of Applied Physics, vol. 40, pp. 1586-1588, 1969.
[28] S. Mrowec and Z. Grzesik, "Oxidation of nickel and transport properties of nickel oxide," Journal of Physics and Chemistry of Solids, vol. 65, pp. 1651-1657, 2004.
[29] F. Kröger, "Point defects and phase stability of transition metal compounds," Journal of Physics and Chemistry of Solids, vol. 29, pp. 1889-1899, 1968.
[30] G. Turgut, E. Sonmez, and S. Duman, "Determination of certain sol-gel growth parameters of nickel oxide films," Ceramics International, vol. 41, pp. 2976-2989, 2015.
[31] Y. Xi, Y. Hsu, A. Djurišić, A. Ng, W. Chan, H. Tam, et al., "NiO∕ ZnO light emitting diodes by solution-based growth," Applied Physics Letters, vol. 92, p. 113505, 2008.
[32] Y. Zhao, H. Wang, C. Wu, Z. Shi, F. Gao, W. Li, et al., "Structures, electrical and optical properties of nickel oxide films by radio frequency magnetron sputtering," Vacuum, vol. 103, pp. 14-16, 2014.
[33] A. Wisitsoraat, A. Tuantranont, E. Comini, G. Sberveglieri, and W. Wlodarski, "Characterization of n-type and p-type semiconductor gas sensors based on NiOx doped TiO2 thin films," Thin Solid Films, vol. 517, pp. 2775-2780, 2009.
[34] M. J. I. S. M. Hajji and H. Ezzaouia, "Synthesis and Characterization of nickel oxide thin films," 2014.
[35] Y.-H. You, B.-S. So, J.-H. Hwang, W. Cho, S. S. Lee, T.-M. Chung, et al., "Impedance spectroscopy characterization of resistance switching NiO thin films prepared through atomic layer deposition," Applied Physics Letters, vol. 89, p. 222105, 2006.
[36] C. E. Patrick and F. Giustino, "Structural and electronic properties of semiconductor sensitized solar‐cell interfaces," Advanced Functional Materials, vol. 21, pp. 4663-4667, 2011.
[37] 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.
[38] 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.
[39] A. Hartanto, X. Ning, Y. Nakata, and T. Okada, "Growth mechanism of ZnO nanorods from nanoparticles formed in a laser ablation plume," Applied Physics A, vol. 78, pp. 299-301, 2004.
[40] X. Fang, J. Li, D. Zhao, D. Shen, B. Li, and X. Wang, "Phosphorus-doped p-type ZnO nanorods and ZnO nanorod p−n homojunction LED fabricated by hydrothermal method," The Journal of Physical Chemistry C, vol. 113, pp. 21208-21212, 2009.
[41] Z. Yin, S. Wu, X. Zhou, X. Huang, Q. Zhang, F. Boey, et al., "Electrochemical deposition of ZnO nanorods on transparent reduced graphene oxide electrodes for hybrid solar cells," Small, vol. 6, pp. 307-312, 2010.
[42] X. Jiaqiang, C. Yuping, C. Daoyong, and S. Jianian, "Hydrothermal synthesis and gas sensing characters of ZnO nanorods," Sensors and Actuators B: Chemical, vol. 113, pp. 526-531, 2006.
[43] 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.
[44] M. Faisal, A. A. Ismail, A. A. Ibrahim, H. Bouzid, and S. A. Al-Sayari, "Highly efficient photocatalyst based on Ce doped ZnO nanorods: Controllable synthesis and enhanced photocatalytic activity," Chemical Engineering Journal, vol. 229, pp. 225-233, 2013.
[45] P. Yang, H. Yan, S. Mao, R. Russo, J. Johnson, R. Saykally, et al., "Controlled growth of ZnO nanowires and their optical properties," Advanced Functional Materials, vol. 12, p. 323, 2002.
[46] 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.
[47] L. Vayssieres, "Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions," Advanced Materials, vol. 15, pp. 464-466, 2003.
[48] R. Kumar, O. Al-Dossary, G. Kumar, and A. Umar, "Zinc oxide nanostructures for NO2 gas–sensor applications: A review," Nano-Micro Letters, vol. 7, pp. 97-120, 2015.
[49] E. Rhoderick and R. Williams, "Metal–Semiconductor Contacts, Clarendon Press, Oxford 1988."
[50] S. M. Sze, Semiconductor devices: physics and technology: John Wiley & Sons, 2008.
[51] 吳富慧 and 曾淑玲, "主題館藏: 半導體元件," 清華大學圖書館館訊, 2011.
[52] S. M. Sze and K. K. Ng, Physics of semiconductor devices: John wiley & sons, 2006.
[53] S. O. Kasap and R. K. Sinha, Optoelectronics and photonics: principles and practices vol. 340: Prentice Hall Upper Saddle River, 2001.
[54] H. Alexander, "Photodetectors test pulsed laser diodes," Photonics Spectra, vol. 36, pp. 60-62, 2002.
[55] Z. Zhang, Q. Liao, Y. Yu, X. Wang, and Y. Zhang, "Enhanced photoresponse of ZnO nanorods-based self-powered photodetector by piezotronic interface engineering," Nano Energy, vol. 9, pp. 237-244, 2014.
[56] C. V. Stan, C. M. Beavers, M. Kunz, and N. Tamura, "X-Ray Diffraction under Extreme Conditions at the Advanced Light Source," Quantum Beam Science, vol. 2, p. 4, 2018.