本實驗使用溶膠凝膠法在矽基板上沉積氧化鋅薄膜，並藉由改變薄膜的層數、鋅的濃度、鋁摻雜濃度、退火的方式(爐退火與快速退火)等製程參數，對薄膜的微結構與發光性質的影響進行比較。在薄膜材料的性質分析上，分別以低掠角X光繞射儀(GIXRD)分析其微結構與結晶相；以掃描式電子顯微鏡(SEM)觀察薄膜表面形貌；以拉曼光譜(Raman)分析材料鍵結行為；以光激發螢光光譜(photoluminescence, PL)觀察其發光行為性質。
在使用多層的氧化鋅薄膜的實驗中Zn濃度0.7 mol/L的三層氧化鋅薄膜呈現明顯的(002)結晶優選強度比；在三層氧化鋅薄膜中使用爐退火800℃時在PL光譜有明顯的可見光發光強度，經過高斯擬合成兩個峰值，位置在524 nm(2.36eV)與571 nm(2.71eV)，這兩波峰訊號來自氧化鋅的氧空缺所產生的深層能階發光，透過使用快速退火的方式在溫度800℃時可以降低缺陷發光強度。鋁摻雜氧化鋅薄膜實驗將改善氧化鋅的電阻特性，實驗結果為使用鋁摻雜濃度3 %在爐退火700℃時有比較好的電阻性質(3.675x103 μΩ-cm)，並且在PL光譜中具有UV發光強度。

In this study, we used the sol-gel method to prepare ZnO films and Al doped ZnO films on Si substrate at room temperature. We investigated how the number of multi-layer structure, annealing temperature and annealing time affect the ZnO films, and the Al doping affects the AZO films. The material properties include micro-structure, surface morphology, bonding and luminescence behaviors of the ZnO and Al doped ZnO films. We used X-ray diffraction (XRD) to analyze crystal phase, scanning electron microscope (SEM) to analyze surface morphology, Raman spectroscopy to analyze bonding, photoluminescence (PL) to measure band gap of the ZnO and AZO films. Then we used these results to explain our experimental data.
According to the results of experiments, the zinc concentration of 0.7 mol/L with preferred orientation (002) on three-layers ZnO thin film. The PL spectra of ZnO thin films by furnace annealed 800℃ (FA) showed a board peak in visible light region. The PL peak of ZnO film at FA 800℃can be fitted into two Gaussian peak at 524 nm (2.36 eV) and 571 nm (2.71 eV) which were attributed to deep-level emissions of oxygen vacancies. Use of rapid thermal annealing can reduce visible emission intensity of PL spectra. The resistance properties are improved by Al doping ZnO thin films. The experimental results for the aluminum doping concentration of 3% and furnace annealing 700℃, there is good resistance(3.675x103 μΩ-cm) properties, and in the PL spectra in the UV luminescence intensity.

[1] H. Ohta, M. Orita, M. Hirano, and H. Hosono, "Fabrication and characterization of ultraviolet-emitting diodes composed of transparent p-n heterojunction, p-SrCu2O2 and n-ZnO," Journal of Applied Physics, vol. 89, pp. 5720-5725, 2001.
[2] D. C. Look, "Recent advances in ZnO materials and devices," Materials Science and Engineering B-Solid State Materials for Advanced Technology, vol. 80, pp. 383-387, 2001.
[3] T. Yamamoto, T. Shiosaki, and A. Kawabata, "Characterization of ZnO piezoelectric films prepared by RF planar-magnetron sputtering," Journal of Applied Physics, vol. 51, pp. 3113-3120, 1980.
[4] Y. Liu, C. R. Gorla, S. Liang, N. Emanetoglu, Y. Lu, H. Shen, and M. Wraback, "Ultraviolet detectors based on epitaxial ZnO films grown by MOCVD," Journal of Electronic Materials, vol. 29, pp. 69-74, 2000.
[5] Y. Segawa, A. Ohtomo, M. Kawasaki, H. Koinuma, Z. K. Tang, P. Yu, and G. K. L. Wong, "Growth of ZnO thin film by laser MBE: Lasing of exciton at room temperature," Physica Status Solidi B-Basic Research, vol. 202, pp. 669-672, 1997.
[6] M. Ohyama, H. Kozuka, and T. Yoko, "Sol-gel preparation of ZnO films with extremely preferred orientation along (002) plane from zinc acetate solution," Thin Solid Films, vol. 306, pp. 78-85, 1997.
[7] R. Zamiri, A. Zakaria, H. A. Ahangar, M. Darroudi, A. K. Zak, and G. P. C. Drummen, "Aqueous starch as a stabilizer in zinc oxide nanoparticle synthesis via laser ablation," Journal of Alloys and Compounds, vol. 516, pp. 41-48, 2012.
[8] S. Li and G. W. Yang, "Phase Transition of II-VI Semiconductor Nanocrystals," Journal of Physical Chemistry C, vol. 114, pp. 15054-15060, 2010.
[9] J. H. Guo, L. Vayssieres, C. Persson, R. Ahuja, B. Johansson, and J. Nordgren, "Polarization-dependent soft-x-ray absorption of a highly oriented ZnO microrod-array," J Phys Condens Matter, vol. 17, pp. 235-40, 2005.
[10] A. Teke, U. Ozgur, S. Dogan, X. Gu, H. Morkoc, B. Nemeth, J. Nause, and H. O. Everitt, "Excitonic fine structure and recombination dynamics in single-crystalline ZnO," Physical Review B, vol. 70, p. 195207, 2004.
[11] Z. L. Wang, "Novel nanostructures of ZnO for nanoscale photonics, optoelectronics, piezoelectricity, and sensing," Applied Physics A, vol. 88, pp. 7-15, 2007.
[12] X. D. Wang, J. H. Song, J. Liu, and Z. L. Wang, "Direct-current nanogenerator driven by ultrasonic waves," Science, vol. 316, pp. 102-105, 2007.
[13] D. G. Baik and S. M. Cho, "Application of sol-gel derived films for ZnO/n-Si junction solar cells," Thin Solid Films, vol. 354, pp. 227-231, 1999.
[14] D. B. Thompson, J. J. Richardson, S. P. DenBaars, and F. F. Lange, "Light Emitting Diodes with ZnO Current Spreading Layers Deposited from a Low Temperature Aqueous Solution," Applied Physics Express, vol. 2, p. 042101, 2009.
[15] H.-L. Yip, S. K. Hau, N. S. Baek, H. Ma, and A. K. Y. Jen, "Polymer Solar Cells That Use Self-Assembled-Monolayer- Modified ZnO/Metals as Cathodes," Advanced Materials, vol. 20, pp. 2376-2382, 2008.
[16] X. Fang, Y. Bando, U. K. Gautam, T. Zhai, H. Zeng, X. Xu, M. Liao, and D. Golberg, "ZnO and ZnS Nanostructures: Ultraviolet-Light Emitters, Lasers, and Sensors," Critical Reviews in Solid State and Materials Sciences, vol. 34, pp. 190-223, 2009.
[17] D. M. Bagnall, Y. F. Chen, M. Y. Shen, Z. Zhu, T. Goto, and T. Yao, "Room temperature excitonic stimulated emission from zinc oxide epilayers grown by plasma-assisted MBE," Journal of Crystal Growth, vol. 184, pp. 605-609, 1998.
[18] H. Lin, S. Zhou, H. Teng, T. Jia, X. Hou, S. Gu, S. Zhu, Z. Xie, P. Han, and R. Zhang, "Polishing of (100) γ-LiAlO2 wafer and its effect on the epitaxial growth of ZnO films by MOCVD," Journal of Alloys and Compounds, vol. 479, pp. L8-L10, 2009.
[19] H. S. Kang, J. S. Kang, S. S. Pang, E. S. Shim, and S. Y. Lee, "Variation of light emitting properties of ZnO thin films depending on post-annealing temperature," Materials Science and Engineering: B, vol. 102, pp. 313-316, 2003.
[20] B. X. Lin, Z. X. Fu, Y. B. Jia, and G. H. Liao, "Defect photoluminescence of undoping ZnO films and its dependence on annealing conditions," Journal of the Electrochemical Society, vol. 148, pp. G110-G113, 2001.
[21] A. R. Hutson, "Hall Effect Studies of Doped Zinc Oxide Single Crystals," Physical Review, vol. 108, pp. 222-230, 1957.
[22] D. C. Look, J. W. Hemsky, and J. R. Sizelove, "Residual native shallow donor in ZnO," Physical Review Letters, vol. 82, pp. 2552-2555, 1999.
[23] A. B. Djurišić, Y. H. Leung, K. H. Tam, L. Ding, W. K. Ge, H. Y. Chen, and S. Gwo, "Green, yellow, and orange defect emission from ZnO nanostructures: Influence of excitation wavelength," Applied Physics Letters, vol. 88, p. 103107, 2006.
[24] A. B. Djurišić, Y. H. Leung, K. H. Tam, Y. F. Hsu, L. Ding, W. K. Ge, Y. C. Zhong, K. S. Wong, W. K. Chan, H. L. Tam, K. W. Cheah, W. M. Kwok, and D. L. Phillips, "Defect emissions in ZnO nanostructures," Nanotechnology, vol. 18, p. 095702, 2007.
[25] M. Ramani, S. Ponnusamy, and C. Muthamizhchelvan, "Zinc oxide nanoparticles: A study of defect level blue–green emission," Optical Materials, vol. 34, pp. 817-820, 2012.
[26] C. G. Van de Walle, "Defect analysis and engineering in ZnO," Physica B-Condensed Matter, vol. 308, pp. 899-903, 2001.
[27] K. Vanheusden, W. L. Warren, C. H. Seager, D. R. Tallant, J. A. Voigt, and B. E. Gnade, "Mechanisms behind green photoluminescence in ZnO phosphor powders," Journal of Applied Physics, vol. 79, p. 7983, 1996.
[28] B. Panigrahy, M. Aslam, D. S. Misra, M. Ghosh, and D. Bahadur, "Defect-Related Emissions and Magnetization Properties of ZnO Nanorods," Advanced Functional Materials, vol. 20, pp. 1161-1165, 2010.
[29] "Wurtzite-structure materials (Group-III nitrides, ZnO)," Infrared Ellipsometry on Semiconductor Layer Structures: Phonons, Plasmons, and Polaritons, vol. 209, pp. 109-145, 2004.
[30] J. D. Ye, S. L. Gu, S. M. Zhu, F. Qin, S. M. Liu, W. Liu, X. Zhou, L. Q. Hu, R. Zhang, Y. Shi, and Y. D. Zheng, "Production of high-quality ZnO films by the two-step annealing method," Journal of Applied Physics, vol. 96, p. 5308, 2004.
[31] S. B. Yahia, L. Znaidi, A. Kanaev, and J. P. Petitet, "Raman study of oriented ZnO thin films deposited by sol-gel method," Spectrochim Acta A Mol Biomol Spectrosc, vol. 71, pp. 1234-8, 2008.
[32] M. Kashif, Y. Al-Douri, U. Hashim, M. E. Ali, S. M. U. Ali, and M. Willander, "Characterisation, analysis and optical properties of nanostructure ZnO using the sol–gel method," Micro & Nano Letters, vol. 7, p. 163, 2012.
[33] B. T. Khuriyakub, G. S. Kino, and P. Galle, "Studies of optimum conditions for growth of RF-sputtered ZnO films," Journal of Applied Physics, vol. 46, pp. 3266-3272, 1975.
[34] B. D. Yao, Y. F. Chan, and N. Wang, "Formation of ZnO nanostructures by a simple way of thermal evaporation," Applied Physics Letters, vol. 81, p. 757, 2002.
[35] T. Minami, K. Oohashi, S. Takata, T. Mouri, and N. Ogawa, "Preparations of ZnO-Al transparent conducting films by DC magnetron sputtering," Thin Solid Films, vol. 193, pp. 721-729, 1990.
[36] K. Haga, T. Suzuki, Y. Kashiwaba, H. Watanabe, B. P. Zhang, and Y. Segawa, "High-quality ZnO films prepared on Si wafers by low-pressure MO-CVD," Thin Solid Films, vol. 433, pp. 131-134, 2003.
[37] M. E. Fragalà , G. Malandrino, M. M. Giangregorio, M. Losurdo, G. Bruno, S. Lettieri, L. S. Amato, and P. Maddalena, "Structural, Optical, and Electrical Characterization of ZnO and Al-doped ZnO Thin Films Deposited by MOCVD," Chemical Vapor Deposition, pp. n/a-n/a, 2009.
[38] A. El-Shaer, A. C. Mofor, A. Bakin, M. Kreye, and A. Waag, "High-quality ZnO layers grown by MBE on sapphire," Superlattices and Microstructures, vol. 38, pp. 265-271, 2005.
[39] A. Bakin, A. El-Shaer, A. Che Mofor, M. Kreye, A. Waag, F. Bertram, J. Christen, M. Heuken, and J. Stoimenos, "MBE growth of ZnO layers on sapphire employing hydrogen peroxide as an oxidant," Journal of Crystal Growth, vol. 287, pp. 7-11, 2006.
[40] L. Znaidi, "Sol–gel-deposited ZnO thin films: A review," Materials Science and Engineering: B, vol. 174, pp. 18-30, 2010.
[41] D. H. Bao, H. S. Gu, and A. X. Kuang, "Sol-gel-derived c-axis oriented ZnO thin films," Thin Solid Films, vol. 312, pp. 37-39, 1998.
[42] 陳光華, "奈米薄膜技術與應用," 五南出版社, 2005.
[43] H. K. Masashi Ohyama, Toshinobu Yoko, Sumio Sakka, "Preparation of ZnO Films with Preferential Oriention by Sol-Gel Method," Journal of the Ceramic Society of Japan, vol. 104, pp. 296-300, 1996.
[44] R. Ghosh, B. Mallik, S. Fujihara, and D. Basak, "Photoluminescence and photoconductance in annealed ZnO thin films," Chemical Physics Letters, vol. 403, pp. 415-419, 2005.
[45] Y.-S. Kim, W.-P. Tai, and S.-J. Shu, "Effect of preheating temperature on structural and optical properties of ZnO thin films by sol–gel process," Thin Solid Films, vol. 491, pp. 153-160, 2005.
[46] J. H. Lee, K. H. Ko, and B. O. Park, "Electrical and optical properties of ZnO transparent conducting films by the sol-gel method," Journal of Crystal Growth, vol. 247, pp. 119-125, 2003.
[47] H. Li, J. Wang, H. Liu, C. Yang, H. Xu, X. Li, and H. Cui, "Sol–gel preparation of transparent zinc oxide films with highly preferential crystal orientation," Vacuum, vol. 77, pp. 57-62, 2004.
[48] H. Li, J. Wang, H. Liu, H. Zhang, and X. Li, "Zinc oxide films prepared by sol–gel method," Journal of Crystal Growth, vol. 275, pp. e943-e946, 2005.
[49] D. Raoufi and T. Raoufi, "The effect of heat treatment on the physical properties of sol–gel derived ZnO thin films," Applied Surface Science, vol. 255, pp. 5812-5817, 2009.
[50] K.-m. Lin and P. Tsai, "Growth mechanism and characterization of ZnO: Al multi-layered thin films by sol–gel technique," Thin Solid Films, vol. 515, pp. 8601-8604, 2007.
[51] S.-Y. Kuo, F.-I. Lai, W.-C. Chen, C.-P. Cheng, H.-C. Kuo, and S.-C. Wang, "Ultraviolet Lasing of Sol–Gel-Derived Zinc Oxide Polycrystalline Films," Japanese Journal of Applied Physics, vol. 45, pp. 3662-3665, 2006.
[52] S. J. Kwon, J.-H. Park, and J.-G. Park, "Wrinkling of a sol-gel-derived thin film," Physical Review E, vol. 71, p. 011604, 2005.
[53] J. B. Miller, H.-J. Hsieh, B. H. Howard, and E. Broitman, "Microstructural evolution of sol–gel derived ZnO thin films," Thin Solid Films, vol. 518, pp. 6792-6798, 2010.
[54] J. M. Calleja and M. Cardona, "Resonant Raman scattering in ZnO," Physical Review B, vol. 16, pp. 3753-3761, 1977.
[55] K. Senthilkumar, M. Tokunaga, H. Okamoto, O. Senthilkumar, J. Lin, B. Urban, A. Neogi, and Y. Fujita, "Multiphonon scattering and non-radiative decay in ZnO nanoparticles," physica status solidi (c), vol. 7, pp. 1586-1588, 2010.
[56] A. van Dijken, E. A. Meulenkamp, D. Vanmaekelbergh, and A. Meijerink, "The luminescence of nanocrystalline ZnO particles: the mechanism of the ultraviolet and visible emission," Journal of Luminescence, vol. 87-9, pp. 454-456, 2000.
[57] Z. Q. Xu, H. Deng, Y. Li, Q. H. Guo, and Y. R. Li, "Characteristics of Al-doped c-axis orientation ZnO thin films prepared by the sol–gel method," Materials Research Bulletin, vol. 41, pp. 354-358, 2006.
[58] S.-Y. Kuo, W.-C. Chen, F.-I. Lai, C.-P. Cheng, H.-C. Kuo, S.-C. Wang, and W.-F. Hsieh, "Effects of doping concentration and annealing temperature on properties of highly-oriented Al-doped ZnO films," Journal of Crystal Growth, vol. 287, pp. 78-84, 2006.
[59] D. Behera and B. S. Acharya, "Nano-star formation in Al-doped ZnO thin film deposited by dip-dry method and its characterization using atomic force microscopy, electron probe microscopy, photoluminescence and laser Raman spectroscopy," Journal of Luminescence, vol. 128, pp. 1577-1586, 2008.
[60] S. Mridha and D. Basak, "Aluminium doped ZnO films: electrical, optical and photoresponse studies," Journal of Physics D: Applied Physics, vol. 40, pp. 6902-6907, 2007.
[61] H. Gao, D. Gao, G. Yang, J. Zhang, J. Zhang, Z. Shi, and D. Xue, "Effect of annealing temperature on the magnetic properties of Zn0.97Al0.03O nanoparticles," physica status solidi (a), vol. 208, pp. 2454-2459, 2011.