研究生: |
梁志豪 Liang, Chih-Hao |
---|---|
論文名稱: |
製程方法與條件對ZnO基底薄膜光電特性之影響 Effect of Processing Methods/Conditions on the Electrical and Optical Properties of ZnO-based Thin Film |
指導教授: |
黃文星
Hwang, Weng-Sing |
學位類別: |
博士 Doctor |
系所名稱: |
工學院 - 材料科學及工程學系 Department of Materials Science and Engineering |
論文出版年: | 2014 |
畢業學年度: | 102 |
語文別: | 英文 |
論文頁數: | 191 |
中文關鍵詞: | ZnO:Al薄膜 、ZnO:Ga薄膜 、陰極電弧沉積 、射頻磁控濺鍍 、疊差 、光電特性 |
外文關鍵詞: | ZnO:Al films, ZnO:Ga films, steered cathodic arc plasma evaporation, radio-frequency magnetron sputtering, stacking faults, electro-optical properties |
相關次數: | 點閱:91 下載:0 |
分享至: |
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
本研究的目的是藉由製程方法與參數的調控達到增進氧化鋅基薄膜的光電特性、降低其製程溫度及提高鍍膜沉積速率。使用的製程方法包含射頻磁控濺鍍與陰極電弧沉積兩種技術,並探討微結構與製程參數及氧化鋅基薄膜的光電特性之相互關係。
使用射頻磁控濺鍍成長氧化ZnO:Al (AZO)薄膜於溫度350 °C的玻璃基材,並施加不同的基材偏壓 (–20 V到–80 V),基材偏壓與微結構及光電特性三者之間的相互關聯性將被有系統地探討。氧化鋅c軸與a軸晶格常數的比值(c/a比值)在基材偏壓高於–60 V有顯著的上升,為薄膜成長時引入的壓縮應力造成。較高的c/a比值誘發產生高密度的基平面疊差,AZO薄膜成長條件在基材偏壓–80 V時有高密度的疊差形成達9.4×105 cm-1,而在最佳成長條件在基材偏壓–50 V時只有疊差高密度3.9×105 cm–1,電性方面顯示低疊差密度的AZO薄膜具有金屬般的導電行為,室溫下的導電率為3.96×10–4 Ω•cm。
氫摻雜濃度與成長溫度對於氫、鋁共摻雜氧化鋅(HAZO)薄膜的結構與光電特性被有系統的研究。二次離子質譜儀圖譜顯示氫離子摻雜濃度在沉積溫度300 °C時顯著地下降,拉曼光譜顯示氫離子佔據氧空抑制缺陷誘發的拉曼振動模態。HAZO薄膜在沉積溫度350 °C時有最佳光電特性90.67 %與電阻率4.89×10-4 Ωcm,電性提升的原因為電中性的非活性缺陷被分解、增加施體能階、鈍化缺陷造成的能階。HAZO薄膜在H/Ar電漿中處理(0-60分鐘)於400 °C下探討其在不同時間的光電特性穩定度。晶粒尺寸、氫摻雜濃度在電漿中處理30分鐘後顯著下降,當H/Ar電漿處理達60分鐘時有高密度的疊差與氧缺陷生成。電性在H/Ar電漿中處理30分鐘內都能保持穩定介於5.8×10-4 Ωcm到6.5×10-4 Ωcm之間。
使用陰極電弧沉積ZnO:Ga (GZO)薄膜厚度(120–520 nm),本技術據有高沉積速率220 nm/min與低沉積溫度120 °C。使用高熔點(1975°C)的GZO陶瓷靶材可有效降低微滴,此外將探討成長機製、微結構、電子傳導行為等特性。穿透式電子顯微鏡分析顯示GZO薄膜直接在非晶基材成長出結晶態的ZnO結構,大部份的晶體型態為柱狀晶結構,伴隨少部份的奈米級的微滴(~100 nm),電阻率與光學最佳值分別為4.72×10-4 Ωcm與 89%的穿透率。AZO薄膜使用高沉積速率(215 nm/min)陰極電弧沉積技術於不同成長溫度(Td = 80-400 °C)。Al3+的摻雜效率隨成長溫度提升到200 °C有最好加值,透光率為87.7%且電阻率為5.48×10−4 Ωcm,然而製程溫度提高到400 °C時有觀察到Al摻雜偏析於晶界導致電性變差。
The aims of this work are to grow the high conductivity and transparency ZnO-based films. The relationships among the processing methods/conditions, microstructure variations and electro-optical properties of the ZnO-based films were investigated. The ZnO-based thin films were deposited by using RF magnetron sputtering or steered cathodic arc plasma evaporation (steered CAPE).
Al-doped ZnO (AZO) films were deposited on the glass substrate with various bias voltages (–20 V to –80 V) at 350 °C by RF magnetron sputtering. The relationships among the bias voltages, microstructure variations, and electro-optical properties of the AZO films were studied. The ratio of c- and a-axis lattice constants (c/a ratio) of the wurtzite structure begins to increase rapidly at –60 V due to the introduction of compressive stresses. The higher c/a ratio induces a high density of basal-plane stacking faults (BSFs) (9.4×105 cm-1) for a high bias to –80 V. The AZO film deposited at –50 V shows a lower density of stacking faults (3.9×105 cm–1), leading to the lowest resistivity (3.96×10–4 Ω cm) and metal-like conductivity. In contrast, the film deposited at –80 V exhibits higher resistivity (1.35×10–3 Ω cm), due to the increasing number of trap states and scattering centers near stacking faults.
The effects of H concentration and deposition temperature (Td), from 150 to 400 °C, on the structural and the electro-optical properties of ZnO co-doped with Al and H (HAZO) films were systematically investigated. The secondary ion mass spectroscopy (SIMS) depth profiles of films indicated the H concentration was slightly reduced until Td reached 300 °C, decreasing dramatically thereafter. Raman spectra confirmed that the H occupied oxygen vacancies and suppressed defect induced Raman mode. The HAZO films deposited at 350 °C had the best average visible transmittance of 90.67 % and resistivity of 4.89×10-4 Ω•cm. The electrical properties of HAZO films were enhanced by an increase in effective donors due to dissociated electrically inactive defects ( ), an increase in shallow donors, and passivating defect states. HAZO films were exposed to H/Ar plasma for various durations (0-60 min) at 400 °C to study the effects of heat treatment in H/Ar plasma on the stability of the electro-optical properties and microstructure variations of the films. The SIMS depth profiles show that the H concentration slightly decreased with increasing Ta up to 30 min. H was significantly out-diffused, enhanced by BSFs and grain boundaries, for Ta values larger than 30 min. The resistivity of the films remained stable in the range of 5.8×10-4 Ω•cm to 6.5×10-4 Ω•cm as Ta was increased from 0 to 30 min, and then increased with further increases in Ta. The electrical properties deteriorated due to a decrease in the crystallite size, high-density BSFs, and the out-diffusion of hydrogen.
Ga-doped ZnO (GZO) thin films with various thicknesses (120–520 nm) are deposited on the glass substrate at a high growth rate of 220 nm/min and a low temperature of 120°C by a steered CAPE. The droplet size is significantly reduced when a high-melting-point (1975°C) GZO ceramic target is adopted. The electrical properties improve with increasing thickness. The lowest resistivity (4.72×10-4 Ω cm) is achieved at the thickness of 520 nm, with a corresponding transmittance of 89 % in the visible region. AZO films were deposited using high-rate (215 nm/min) steered CAPE with a ceramic AZO target at various deposition temperatures (Td = 80-400 °C). The Al3+ doping efficiency was improved by increasing Td; however, the Al segregated to the grain boundary at high Td. The films deposited at 200 °C had the highest figure of merit (2.21×10-2 Ω-1), with a corresponding average transmittance of 87.7% and resistivity of 5.48×10−4 Ω•cm.
[1] K.-C. Lai, C.-C. Liu , C.-H Lu , C.-H. Yeh, M.-P. Houng, Characterization of ZnO:Ga transparent contact electrodes for microcrystalline silicon thin film solar cells, Solar Energy Materials & Solar Cells 94 (2010) 397.
[2] A.Tanaka, M. Hirata, Y. Kiyohara, M. Nakano, K. Omae, M. Shiratani, K. Koga, Review of pulmonary toxicity of indium compounds to animals and humans, Thin Solid Films 518 (2010) 2934.
[3] R. Banerjee, S. Ray, N. Basu, A.K. Batabyal and A.K. Barua, Degradation of tin‐doped indium‐oxide film in hydrogen and argon plasma, Journal of Applied Physics 62 (1987) 912.
[4] E. Fortunato, D. Ginley, H. Hosono, and D. C. Paine, Transparent conducting oxides for photovoltaics, MRS Bulletin 32 (2007) 242.
[5] C.-H. Liang , S.-C. Chen, X. Qi, C.-S. Chen, and C.-C. Yang, Influence of film thickness on the texture, morphology and electro-optical properties of indium tin oxide films, Thin Solid Films 519 (2010) 345.
[6] C.-H. Liang, W.-S. Hwang, Structural and electro-optical properties of hydrogen and aluminum-co-doped zinc oxide films deposited by sputtering at various deposition temperatures, Science of Advanced Materials 5 (2013)1930.
[7] K. Ellmer, Magnetron sputtering of transparent conductive zinc oxide: relation between the sputtering parameters and the electronic properties, Journal of Physics D: Applied Physics 33 (2000) R17.
[8] A. Janotti and C. G. Van de Walle, Fundamentals of zinc oxide as a semiconductor, Reports on Progress in Physics 72 (2009) 126501-1.
[9] T. Minami, Transparent conducting oxide semiconductors for transparent electrodes, Semicondor Science Technology 20 (2005) S35.
[10] M. Grundmann, The Physics of Semiconductors, Springer, Berlin, 2006.
[11] T. Minami, New n-type transparent conducting oxides, MRS Bulletin 25 (2000) 38.
[12] C. G. Granqvist, Transparent conductors as solar energy materials: A panoramic review, Solar Energy Materials & Solar Cells 91 (2007) 1529.
[13] T. Minami, Transparent and conductive multicomponent oxide films prepared by magnetron sputtering, Journal Vacuum Science & Technology A 17 (1999) 1765.
[14] K. Ellmer, A. Klein, and B. Rech, Transparent Conductive Zinc Oxide: Basics and Applications in Thin Film Solar Cell, Springer, Berlin, 2008.
[15] A. Janotti and C. G. Van de Walle, Oxygen vacancies in ZnO, Applied Physics Letters 87 (2005) 122102.
[16] A. Janotti and C. G. Van de Walle, Native point defects in ZnO, Physical Review B 76 (2007) 165202.
[17] S. M .Evans, N. C. Giles, L. E. Halliburton and L. A. Kappers, Further characterization of oxygen vacancies and zinc vacancies in electron-irradiated ZnO, Journal of Applied Physics 103 (2008) 043710.
[18] D. Galland and A. Herve, Temperature dependence of the ESR spectrum of the zinc vacancy in ZnO, Solid State Communications, 14 (1974) 953.
[19] J. Han, P. Q. Mantas, and A. M. R. Senos, Defect chemistry and electrical characteristics of undoped and Mn-doped ZnO, Journal of the European Ceramic Society 22 (2002) 49.
[20] N. Roberts, R.P. Wang, A.W. Sleight, W.W. Warren, 27Al and 69Ga impurity nuclear magnetic resonance in ZnO:Al and ZnO:Ga, Physical Review B 57 (1998) 5734.
[21] K. Ip, M. E. Overberg, Y. W. Heo, D. P. Norton, S. J. Pearton, S. O. Kucheyev, C. Jagadish, J. S. Williams, R. G. Wilson, and J. M. Zavada, Thermal stability of ion-implanted hydrogen in ZnO, Applied Physics Letters 81 (2002) 3996.
[22] A. Singh, S. Chaudhary, and D. K. Pandya, Hydrogen incorporation induced metal-semiconductor transition in ZnO:H thin films sputtered at room temperature, Applied Physics Letters 102 (2013) 172106.
[23] M. Zeuner, H. Neumann, J. Zalman and H. Biederman, Sputter process diagnostics by negative ions, Journal of Applied Physics. 83 (1998) 5083.
[24] N. Ito, N. Oka, Y. Sato, Y. Shigesato, Effects of energetic ion bombardment on structural and electrical properties of Al-Doped ZnO films deposited by RF-superimposed DC magnetron sputtering, Japanese Journal of Applied Physics 49 (2010) 071103.
[25] P. Pokorny, M. Misina, J. Bulı´r, J. Lancok, P. Fitl, J. Musil, M. Novotny, Investigation of the negative Ions in Ar/O2 plasma of magnetron sputtering discharge with Al:Zn target by ion mass spectrometry, Plasma Processes and Polymers 8 (2011) 459.
[26] S. Mahieu, W. P. Leroy, K. Van Aeken, and D. Depla, Modeling the flux of high energy negative ions during reactive magnetron sputtering, Journal of Applied Physics 106 (2009) 093302.
[27] T. Minami, T. Miyata, Present status and future prospects for development of non- or reduced-indium transparent conducting oxide thin films, Thin Solid Films 517 (2008) 1474.
[28] T. Minami, T. Miyata, T. Yamamoto, and H. Toda, Origin of electrical property distribution on the surface of ZnO:Al films prepared by magnetron sputtering, Journal of Vacuum Science & Technology A. 18 (2000) 1584.
[29] K. Tominaga, T. Yuasa, M. Kume, and O. Tada, Influence of Energetic Oxygen Bombardment on Conductive ZnO Films, Japanese Journal of Applied Physics 24 (1985) 944.
[30] A. Bikowski, T. Welzel, K. Ellmer, The correlation between the radial distribution of high-energetic ions and the structural as well as electrical properties of magnetron sputtered ZnO:Al films, Journal of Applied Physics 114 (2013) 223716.
[31] D. M. Sanders, A. Anders, Review of cathodic arc deposition technology at the start of the new millennium, Surface and Coatings Technology 133–134 (2000) 78.
[32] A. Anders, Cathodic Arcs, Springer, New York, 2008.
[33] H. Randhawa, P. C. Johnson, Review of cathodic arc deposition technology at the start of the new millennium, Surface and Coatings Technology 31 (2000) 303.
[34] F. Sanchette, C. Ducros, T. Schmitt, P. Steyer, A. Billard, Nanostructured hard coatings deposited by cathodic arc deposition: From concepts to applications, Surface and Coatings Technology 205 (2011) 5444.
[35] R.L. Boxman, S. Goldsmith, Macroparticle contamination in cathodic arc coatings: generation, transport and control, Surface and Coatings Technology 52 (1992) 39.
[36] G.W. McClure, Plasma expansion as a cause of metal displacement in vacuum‐arc cathode spots, Journal of Applied Physics 45 (1974) 2078.
[37] P.J. Martin, A. Bendavid, Review of the filtered vacuum arc process and materials deposition, Thin Solid Films 394 (2001) 1.
[38] H. Randhawa, Cathodic arc plasma deposition technology, Thin Solid Films 167 (1988) 175.
[39] B. D. Cullity and S. R. Stock, Elements of X-Ray Diffraction, Prentice
Hall, New Jersey, 2001.
[40] Y. Yan, G. M. Dalpian, M. M. Al-Jassim and S. H. Wei, Energetics and electronic structure of stacking faults in ZnO, Physical Review B 70 (2004) 193206.
[41] M.-S. Oh, D.-K. Hwang, Y-S. Choi, J.-W. Kang, S.-J. Park, C.-S. Hwang and K.-I. Cho, Microstructural properties of phosphorus-doped p-type ZnO grown by radio-frequency magnetron sputtering, Applied Physics Letters 93 (2008) 111905.
[42] S. H. Lim and D. Shindo, Defects and interfaces in an epitaxial ZnO/LiTaO3 heterostructure, Journal of Applied Physics 88 (2000) 5107.
[43] D. Gerthsen, D. Litvinov, T. Gruber, C. Kirchner and A. Waag, Origin and consequences of a high stacking fault density in epitaxial ZnO layers, Applied Physics Letters 81 (2002) 3972.
[44] M. Schirra, R. Schneider, A. Reiser, G. M. Prinz, M. Feneberg, J. Biskupek, U. Kaiser, C. E. Krill, K. Thonke and R. Sauer, Stacking fault related 3.31-eV luminescence at 130-meV acceptors in zinc oxide, Physical Review B 77 (2002) 125215.
[45] S. Hayamizu, H. Tabata, H. Tanaka and T. Kawai, Preparation of crystallized zinc oxide films on amorphous glass substrates by pulsed laser deposition, Journal of Applied Physics 80 (1996) 787.
[46] E. J. Mittemeijer, P. Scardi, Diffraction analysis of the microstructure of materials, New York, Springer, 2004.
[47] K. H. Ri, Y. Wang, W. L. Zhou, J. X. Gao, X. J. Wang, J. Yu, The structural properties of Al doped ZnO films depending on the thickness and their effect on the electrical properties, Applied Surface Science 258 (2011) 1283.
[48] J. A. Thornton and D. W. Hoffman, Stress-related effects in thin films, Thin Solid Films 171 (1989) 5.
[49] J. D. Kamminga, Th. H. de Keijser, R. Delhez and E. J. Mittemeijer, On the origin of stress in magnetron sputtered TiN layers, Journal of Applied Physics 88 (2000) 6332.
[50] A. J. Detor, A. M. Hodge, E. Chason, Y. Wang, H. Xu, M. Conyers, A. Nikroo and A. Hamza, Stress and microstructure evolution in thick sputtered films, Acta Materialia 57 (2009) 2055.
[51] C. M. Gilmore and J. A. Sprague, Molecular dynamics simulation of defect formation during energetic Cu deposition, Thin Solid Films 419 (2002) 18.
[52] G. Abadias, Y. Y. Tse, P. Guérin and V. Pelosin, Interdependence between stress, preferred orientation, and surface morphology of nanocrystalline TiN thin films deposited by dual ion beam sputtering, Journal of Applied Physics 99 (2006) 113519.
[53] N. Ito, N. Oka, Y. Sato and Y. Shigesato, Effects of Energetic Ion Bombardment on Structural and Electrical Properties of Al-Doped ZnO Films Deposited by RF-Superimposed DC Magnetron Sputtering, Japanese Journal of Applied Physics 49 (2010) 071103.
[54] S. J. Zinkle and C. J. Kinoshita, Defect production in ceramics, J Journal of Nuclear Materials 251 (1997) 200.
[55] Q. S. Paduano, D. W. Weyburne and A. J. Drehman, An X-ray diffraction technique for analyzing basal-plane stacking faults in GaN, Physica Status Solidi A 207 (2010) 2446.
[56] A. Janotti and C. G. Van de Walle, Native point defects in ZnO, Physical Review B 76 (2007) 165202.
[57] K. Suzuki, M. Ichihara, S. Takeuchi, High-resolution electron microscopy of extended in Wurtzite crystals, Japanese Journal of Applied Physics 33 (1994) 1114.
[58] M. A. Moram, C. F. Johnson, J. L. Hollander, M. J. Kappers, C. J. Humpreys, Understanding x-ray diffraction of nonpolar gallium nitride films, Journal of Applied Physics 105 (2009) 113501.
[59] S. K. Hong, H. K. Cho, Structural defects in GaN and ZnO, in Oxide and Nitride Semiconductors: Processing, Properties, and Applications, ed T. Yao, S. K. Hong Berlin, Heidelberg, Springer Berlin Heidelberg, 2009.
[60] D. N. Zakharov, Z. L. Weber, B. Wagner, Z. J. Reitmeier, E. A. Preble, R. F. Davis, Structural TEM study of nonpolar a-plane gallium nitride grown on (1120) 4H-SiC by organometallic vapor phase epitaxy, Physical Review B 71 (2005) 235334.
[61] S. Takeuchi, K. Suzuki, Stacking fault energies of tetrahedrally coordinated crystals, Physica Status Solidi A 171 (1999) 99.
[62] J. A. Chisholm, P. D. Bristowe, A first principles investigation of stacking fault energies and bonding in wurtzite materials, Journal of Physics: Condensed Matter 11 (1999) 5057.
[63] H. P. Sun, X. Q. Pan, X. L. Du, Z. X. Mei, Z. Q. Zeng and Q. K. Xue, Microstructure and crystal defects in epitaxial ZnO film grown on Ga modified (0001) sapphire surface, Applied Physics Letters 85 (2004) 4385.
[64] T. Yano and T. Iseki, Swelling and microstructure of AlN irradiated in a fast reactor, Journal of Nuclear Materials 203 (1993) 249.
[65] L. D. Yao, D. Weissenberger, M. Dürrschnabel, D. Gerthsen, I. Tischer, M. Wiedenmann, M. Feneberg, A. Reiser and k. Thonke, Structural and cathodoluminescence properties of ZnO nanorods after Ga implantation and annealing, Journal of Applied Physics 105 (2009) 103521.
[66] T. Yoshiie, H. Iwanaga, N. Shibata, K. Suzuki and S. Takeuchi, Studies of dislocation loops produced by irradiation of ZnO in a high-voltage electron microscope, Philosophical Magazine A 41 (1980) 935.
[67] I. Yonenaga, H. Koizumi, Y. Ohno and T. Taishi, High-temperature strength and dislocation mobility in the wide band-gap ZnO: Comparison with various semiconductors, Journal of Applied Physics 103 (2008) 093502.
[68] Y. J. Park, H. N. Kim, H. H. Shin, Effects of deposition temperature on the crystallinity of Ga-doped ZnO thin films on glass substrates prepared by sputtering method , Applied Surface Science 255 (2009) 7532.
[69] N. W. Ashcroft and N. D. Mermin, Solid State Physics New York: Holt, Rinehart and Winston, 1976.
[70] V. Bhosle, A. Tiwari and J. Narayan, Electrical properties of transparent and conducting Ga doped ZnO, Journal of Applied Physics 100 (2006) 033713.
[71] O. Bamiduro, H. Mustafa, R. Mundle, R. B. Konda and A. K. Pradhan, Metal-like conductivity in transparent Al:ZnO films, Applied Physics Letters 90 (2007) 252108.
[72] W. L. Wangn,Y. T. Ho, K. A. Chiu, C. Y. Peng and L. Chang, Structural property of m-plane ZnO epitaxial film grown on LaAlO3 (1 12) substrate, Journal of Crystal Growth 312 (2010) 1179.
[73] J. Narayan, K. Dovidenko, A. K. Sharma and S. Oktyabrsky, Defects and interfaces in epitaxial ZnO/α-Al2O3 and AlN/ZnO/α-Al2O3 heterostructures , Journal of Applied Physics 84 (1998) 2597.
[74] H. Von Wenckstern, S. Weinhold, G. Biehne, R. Pickenhain, H. Schmidt, H. Hochmuth and M. Grundmann, Donor Levels in ZnO, Advances in Solid State Physics 45 (2005) 263.
[75] F. Herklotz, E. V. Lavrov, J. Weber, G. V. Mamin, Y. S. Kutin, M. A. Volodin and S. B. Orlinskii, Identification of shallow Al donors in ZnO, Physica Status Solidi B 248 (2011)1532.
[76] K. Vanheudsen, W. L. Warren, C. H. Scager, D. R. Tallant, J. A. Voigt and B. E. Gnade, Mechanisms behind green photoluminescence in ZnO phosphor powders, Journal of Applied Physics 79 (1996) 7983.
[77] M. A. Lopez de la Torre, Z. Sefrioui, D. Arias, M. Varela, J. E. Villegas, C. Ballesteros, C. Leon and J. Santamarı´a, Electron-electron interaction and weak localization effects in badly metallic SrRuO3, Physical Review B 63 (2001) 052403.
[78] B. L. Altshuler and A. G. Aronov, Electron-Electron Interaction in Disordered Conductors, edited by A. L. Efros and M.Pollak Amsterdam, North-Holland, 1985.
[79] E. J. Guo, H. Guo, H. Lu, K. Jin, M. He and G. Yang, Structure and characteristics of ultrathin indium tin oxide films, Applied Physics Letters 98 (2011) 011905.
[80] V. Bhosle, A. Tiwari and J. Narayan, Electrical properties of transparent and conducting Ga doped ZnO, Journal of Applied Physics 100 (2006) 033713.
[81] M. Bazzani, A. Neroni, A. Calzolari and A. Catellani, Optoelectronic properties of Al:ZnO: Critical dosage for an optimal transparent conductive oxide, Applied Physics Letters 98 (2011) 121907.
[82] M. Vinnichenko, R. Gago, S. Cornelius, N. Shevchenko, A. Rogozin, A. Kolitsch, F. Munnik, W. Möller, Establishing the mechanism of thermally induced degradation of ZnO:Al electrical properties using synchrotron radiation, Applied Physics Letters 96 (2010) 141907.
[83] A. K. Srivastava, J. Kumar, Effect of aluminum addition on the optical, morphology and electrical behavior of spin coated zinc oxide thin films, AIP advance 1 (2011) 032153.
[84] B. Nasr, S. Dasgupta, D. Wang, N. Mechau, R. Kruk, and H. Hahn, Electrical resistivity of nanocrystalline Al-doped zinc oxide films as a function of Al content and the degree of its segregation at the grain boundaries, Journal of Applied Physics 108 (2010) 103721.
[85] N. Ohashi, T. Ishigaki, N. Okada, H.Taguchi, I. Sakaguchi, S. Hishita, T.Sekiguchi and H. Haneda, Passivation of active recombination centers in ZnO by hydrogen doping, Journal of Applied Physics 93 (2003) 6386.
[86] K. Ip, M. E. Overberg, Y. W. Heo, D. P. Norton, S. J. Pearton, S. O. Kucheyev, C. Jagadish, J. S. Williams, R. G. Wilson and J. M. Zavada, Thermal stability of ion-implanted hydrogen in ZnO, Applied Physics Letters 81 (2002) 3996.
[87] L.-Y.Chen, W.-H. Chen, J.-J.Wang, F. C.-N. Hong, Y.-K. Su, Hydrogen-doped high conductivity ZnO films deposited by radio-frequency magnetron sputtering, Applied Physics Letters 85 (2004) 5628.
[88] K. Ip, M. E. Overberg, Y. W. Heo, D. P. Norton, S. J. Pearton, C. E. Stutz, B. Luo, F. Ren, D. C. Look and J. M. Zavada, Hydrogen incorporation and diffusivity in plasma-exposed bulk ZnO, Applied Physics Letters 82 (2003) 385.
[89] R. Cebulla, R. Wendt, K. Ellmer, Al-doped zinc oxide films deposited by simultaneous rf and dc excitation of a magnetron plasma: Relationships between plasma parameters and structural and electrical film properties, Journal of Applied Physics 83 (1998) 1087.
[90] X. H. Huang, C. B. Tay, Z. Y. Zhan, C. Zhang, L. X. Zheng, T. Venkatesan and S. J. Chua, Universal photoluminescence evolution of solution-grown ZnO nanorods with annealing: important role of hydrogen donor, CrystEngComm 13 (2011) 7032.
[91] Ü. Özgür, Ya. I. Alivov, C. Liu, A. Teke, M. A. Reshchikov, S. Doğan, V. Avrutin, S.-J. Cho, and H. Morkoç, A comprehensive review of ZnO materials and devices, Journal of Applied Physics 98 (2005) 041301.
[92] P. Sundara Venkatesh, V. Purushothaman, S. Esakki Muthu, S. Arumugam, V. Ramakrishnan, K. Jeganathan and K. Ramamurthi, Role of point defects on the enhancement of room temperature ferromagnetism in ZnO nanorods, CrystEngComm 14 (2012) 4713.
[93] C. F. Windisch, Jr., G. J. Exarhos, C. Yao, and L.-Q. Wang, Raman study of the influence of hydrogen on defects in ZnO, Journal of Applied Physics 101 (2007) 123711.
[94] F. J. Manjón, B. Marí, J. Serrano and A. H. Romero, Silent Raman modes in zinc oxide and related nitrides, Journal of Applied Physics 97 (2005) 053516.
[95] C. Bundesmann, N. Ashkenov, M. Schubert, D. Spemann, T. Butz, E. M. Kaidashev, M. Lorenz, and M. Grundmann, Raman scattering in ZnO thin films doped with Fe, Sb, Al, Ga, and Li, Applied Physics Letters 83 (2003) 1974.
[96] Z. Liliental-Weber, D. Zakharov, J. Jasinski, M.A. O’Keefe and H. Morkoc, Screw Dislocations in GaN Grown by Different Methods, MicroscopyAND Microanalysis 10 (2004) 47.
[97] V. Narayanan, K. Lorenz, Wook Kim and S. Mahajan, Origins of threading dislocations in GaN epitaxial layers grown on sapphire by metalorganic chemical vapor deposition, Applied Physics Letters 78 (2001) 1544.
[98] K.-K. Kim, H. Tampo, J.-O Song, T.-Y. Seong, S.-J. Park,J.-M. Lee, S.-W. Kim, S. Fujita and S. Niki, Effect of rapid thermal annealing on Al doped n-ZnO films grown by RF-magnetron sputtering, Japanese Journal of Applied Physics 44 (2005) 4776.
[99] N. Ito, N. Oka, Y. Sato and Y. Shigesato, Effects of energetic ion bombardment on structural and electrical properties of Al-doped ZnO films deposited by RF-superimposed DC magnetron sputtering, Japanese Journal of Applied Physics 49 (2010) 071103.
[100] R. B. H. Tahar, T. Ban, Y. Ohya and Y. Takahashi, Tin doped indium oxide thin films: Electrical properties, Journal of Applied Physics 83 (1998) 2631.
[101] L. Hu, J. Huang, H. He, L. Zhu, S. Liu, Y. Jin, L. Sun, Z. Ye, Dual-donor (Zni and VO) mediated ferromagnetism in copper-doped ZnO micron-scale polycrystalline films: a thermally driven defect modulation process, Nanoscale 5 (2013) 3918.
[102] Q. Wan, J. Huang, A. Lu and T. Wang, Degenerate doping induced metallic behaviors in ZnO nanobelts, Applied Physics Letters 93 (2008) 103109.
[103] C. H. Liang, W. L. Wang, W. S. Hwang, High-rate and low-temperature growth of ZnO:Ga thin films by steered cathodic arc plasma evaporation, Applied Surface Science 265 (2013) 621.
[104] V. Bhosle, A. Tiwari and J. Narayan, Electrical properties of transparent and conducting Ga doped ZnO, Journal of Applied Physics 100 (2006) 033713.
[105] H. Von Wenckstern, S. Weinhold, G. Biehne, R. Pickenhain, H. Schmidt, H. Hochmuth and M. Grundmann, Donor Levels in ZnO, Advances in Solid State Physics 45 (2005) 263.
[106] N. H. Alvi, K. ul Hasan, O. Nur, M. Willander, The origin of the red emission in n-ZnO nanotubes/p-GaN white light emitting diodes,Nanoscale Research Letters 6 (2011) 130.
[107] M. He, J. Jung, F. Qiu and Z. Q. Lin, Graphene-based transparent flexible electrodes for polymer solar cells, Journal of Materials Chemistry 22 (2012) 24254.
[108] R. G. Gordon, Criteria for choosing transparent conductor, MRS Bulletin 25 (2000) 52.
[109] J. K. Rath, Low temperature polycrystalline silicon: a review on deposition, physical properties and solar cell applications, Solar Energy Materials & Solar Cells 76 (2003) 431.
[110] J. K. Saha, N. Ohse, K. Hamada, H. Matsui, T. Kobayashi, H. Jia, H. Shirai, Fast deposition of microcrystalline Si films from SiH2Cl2 using ahigh-density microwave plasma source for Si thin-film solar cells, Solar Energy Materials & Solar Cells 94 (2010) 524.
[111] H.-H. Nahm, C. H. Park, Y.-S. Kim, Bistability of Hydrogen in ZnO: Origin of Doping Limit and Persistent Photoconductivity, Scientific Reports 4 (2013) 4124.
[112] S. J. Baik, J. H. Jang, C. H. Lee, W. Y. Cho, and K. S. Lim, Highly textured and conductive undoped ZnO film using hydrogen post-treatment, Applied Physics Letters 70 (1997) 3516.
[113] M. Chen, X. Wang, Y. H. Yu, Z. L. Pei, X. D. Bai, C. Sun, R. F. Huang, L. S.Wen, X-ray photoelectron spectroscopy and auger electron spectroscopy studies of Al-doped ZnO films, Applied Surface Science 158 (2000) 134.
[114] B. K. Shin, T. I. Lee, J. H. Park, K. I. Park, K. J. Ahn, S. K. Park, W. Lee, J. M. Myoung, Preparation of Ga-doped ZnO films by pulsed dc magnetron sputtering with cylindrical rotating target for thin film solar cell applications, Applied Surface Science 258 (2011) 834.
[115] J. F. Chang, W. C. Lin, M. H. Hon, Effects of post-annealing on the structure and properties of Al-doped zinc oxide films, Applied Surface Science 183 (2001) 18.
[116] M. Chen, Z. L. Pei, C. Sun, L. S. Wen, X. Wang, Surface characterization of transparent conductive oxide Al-doped ZnO flms, Journal of Crystal Growth 220 (2000) 254.
[117] C.-H. Liang, J. L. H. Chau, C.-C. Yang, H.-H. Shih, Preparation of amorphous Ga–Sn–Zn–O semiconductor thin films byRF-sputtering method, Materials Science and Engineering B 183 (2014) 17.
[118] K.-K. Kim, H. Tampo, J.-O Song, T.-Y. Seong, S.-J. Park, J.-M. Lee, S.-W. Kim, S. Fujita, and S. Niki, Effect of rapid thermal annealing on Al doped n-ZnO films
grown by RF-magnetron sputtering, Japanese Journal of Applied Physics 44 (2005) 4776.
[119] C.-H. Liang, W.-S. Hwang, and W.-L. Wang, Influence of substrate bias on microstructural variation and electro-optical properties of sputter-deposited ZnO:Al films, Science of Advanced Materials 5 (2013) 844.
[120] D. B. Williams, C.B. Carter, Transmission Electron Microscopy IV: Spectrometry, Plenum Press, New York, 1996, p. 258.
[121] S. Yang, C. C. Kuo, W.-R. Liu, B. H. Lin, H.-C. Hsu, C.-H. Hsu, W. F. Hsieh, Photoluminescence associated with basal stacking faults in c-plane ZnO epitaxial film grown by atomic layer deposition, Applied Physics Letters 100 (2012) 101907.
[122] S. K. Hong, H. K. Cho, Structural Defects in GaN and ZnO, Oxide and Nitride Semiconductors: Processing, Properties, and Applications, edited by T. Yao, S. K. Hong Berlin, Heidelberg, Springer Berlin Heidelberg, 2009, p.266.
[123] D. Gerthsen, D. Litvinov, Th. Gruber, C. Kirchner, and A. Waag, Origin and consequences of a high stacking fault density in epitaxial ZnO layers, Applied Physics Letters 81 (2002) 3972.
[124] M. F. Malek, M. H. Mamat, Z. Khusaimi, M. Z. Sahdan, M. Z. Musa, A. R. Zainun, A. B. Suriani, N. D. Md Sin, S .B. Abd Hamid, M. Rusop, Sonicated sol–gel preparation of nanoparticulate ZnO thin films with various deposition speeds: The highly preferred c-axis (002) orientation enhances the final properties, Journal of Alloys and Compounds 582 (2014) 12.
[125] L. Zhao, G.-J. Shao, X.-J. Qin, S.-H.-Z Han, Concentration-dependent behavior of hydrogen in Al-doped ZnO thin films, Journal of Alloys and Compounds 509 (2011) L297.
[126] G. Haacke, New figure of merit for transparent conductors, Journal of Physics 47 (1976) 4086–4089.
[127] K. Ravichandran, P. Philominathan, Fabrication of antimony doped tin oxide (ATO) films by an inexpensive, simplified spray technique using perfume atomizer, Materials Letters 62 (2008) 2980.
[128] A. Asvarov, A. Abduev, A. Akhmedov, A. Abdullaev, Effects of a high humidity environment and air anneal treatments on the electrical resistivity of transparent conducting ZnO-based thin films, Physica Status Solidi C 7 (2010) 1553.
[129] S. Kohiki, M.Nishitani, T. Wada, Enhanced electrical conductivity of zinc oxide thin films by ion implantation of gallium, aluminum, and boron atoms, Journal of Physics 75 (1994) 2069.
[130] W. D. Münz, I. J. Smith, D. B. Lewis, S. Creasey, Droplet formation on steel substrates during cathodic steered arc metal ion etching, Vacuum 48 (1997) 473.
[131] R. J. Mendelsberg, S. H. N. Lim, Y. K. Zhu, J. Wallig, D. J. Milliron, A. Anders, Achieving high mobility ZnO:Al at very high growth rates by dc filtered cathodic
arc deposition, Journal of Physics D: Applied Physics 44 (2011) 232003.
[132] Y. Zhu, R. J. Mendelsberg, S. H. N. Lim, J. Zhu, J. Han, A. Ander, Improved structural and electrical properties of thin ZnO:Al films by dc filtered cathodic arc deposition, Journal Materials Research 27 (2011) 857.
[133] T. David, S. Goldsmith, R. L. Boxman, Dependence of zinc oxide thin film properties on filtered vacuum arc deposition parameters, Journal of Physics D: Applied Physics 38 (2005) 2407.
[134] H. Takikawa, K. Kimura, R. Miyano, T. Sakakibara, ZnO film formation using a steered and shielded reactive vacuum arc deposition, Thin Solid Films 377-378 (2000) 74.
[135] X.L. Xu, S.P. Lau, B.K. Tay, Structural and optical properties of ZnO thin films produced by filtered cathodic vacuum arc, Thin Solid Films 398–399 (2001) 244.
[136] S. T. Tan, B. J. Chen, X. W. Sun, W. J. Fan, H. S. Kwok, X. H. Zhang, S. J. Chua, Blueshift of optical band gap in ZnO thin films grown by metal-organic chemical-vapor deposition, Journal of Applied Physics 98 (2005) 013505.
[137] J. K. Sheu, K. W. Shu, M. L. Lee, C. J. Tun, G. C. Chi, Effect of thermal annealing on Ga-Doped ZnO films prepared by magnetron sputtering, Journal of The Electrochemical Society 154 (2007) H521.
[138] F. Wu, L. Fang, Y. J. Pan, K. Zhou, Q. L. Huang, C. Y. Kong, Effect of substrate temperature on the structural, electrical and optical properties of ZnO:Ga thin films prepared by RF magnetron sputtering, Physica E 43 (2010) 228.
[139] H. W. Lee, S. P. Lau, Y. G. Wang, B. K. Tay, H. H. Hng, Internal stress and surface morphology of zinc oxide thin films deposited by filtered cathodic vacuum arc technique, Thin Solid Films 458 (2004) 15.
[140] A. Anders, Atomic scale heating in cathodic arc plasma deposition, Applied Physics Letters 80 (2002) 1100.
[141] R. Kelly, The surface binding in slow collisional sputtering, Nucler Instuments and Methods in Physics Research B18 (1987) 388.
[142] E. Mirica, G. Kowach, P. Evans, H. Du, Morphological Evolution of ZnO Thin Films Deposited by Reactive Sputtering, Crystal Growth & Design 4 (2004) 147.
[143] E. Chason, B. W. Sheldon, L. B. Freund, J. A. Floro, S. J. Hearne, Origin of Compressive Residual Stress in Polycrystalline Thin Films, Physical Review Letters 88 (2002) 156103.
[144] B. W. Sheldon, A. Rajamani, A. Bhandari, E. Chason, S. K. Hong, R. Beresford, Competition between tensile and compressive stress mechanisms during Volmer-Weber growth of aluminum nitride films, Journal of Applied Physics 98 (2005) 043509.
[145] J. F. Chang, C. C. Shen, M. H. Hon, Growth characteristics and residual stress of RF magnetron sputtered ZnO:Al films, Ceramics International 29 (2003) 245.
[146] C. Hao, B. Xie, M. Li, H. Wang, Y. Jiang, Y. Song, The influences of high energetic oxygen negative ions and active oxygen on the microstructure and electrical properties of ZnO:Al films by MF magnetron sputtering, Applied Surface Science 258 (2012) 8234.
[147] H. W. Lee, S. P. Lau, Y. G. Wang, B. K. Tay, H. H. Hng, Internal stress and surface morphology of zinc oxide thin films deposited by filtered cathodic vacuum arc technique, Thin Solid Films 458 (2004) 15.
[148] R. Menon, V. Gupta, H. H. Tan, K. Sreenivas, C. Jagadish, Origin of stress in radio frequency magnetron sputtered zinc oxide thin films, Journal Applied Physics 109 (2011) 064905.
[149] R. L. Boxman, I. I. Beilis, E. Gidalevich, V. N. Zhitomirsky, Magnetic Control in Vacuum Arc Deposition: A Review, IEEE Transactions on Plasma science 33 (2005) 1618.
[150] Y. Yoshino, K. Inoue, M. Takeuchi, K. Ohwada, Effects of interface micro structure in crystallization of ZnO thin films prepared by radio frequency sputtering, Vacuum 51 (1998) 601.
[151] I. Shalish, H. Temkin, V. Narayanamurti, Size-dependent surface luminescence in ZnO nanowires, Physical Review B 69 (2004) 245401.
[152] L. L. Yang; Q. X. Zhao, M. Willander, X. J. Liu, M. Fahlman; J. H. Yang, Origin of the surface recombination centers in ZnO nanorods arrays by X-ray photoelectron spectroscopy, Applied Surface Science 256 (2010) 3592.
[153] F. Mitsugi, Y. Umeda, N. Sakai, T. Ikegami, Uniformity of gallium doped zinc oxide thin film prepared by pulsed laser deposition, Thin Solid Films 518 (2010) 6334.
[154] J. D. Russell, D. C. Halls, C. Leach, Grain boundary SEM conductive mode contrast effects in additive zinc oxide ceramics, Acta Materialia 44 (1996) 2431.
[155] P. Feng, Q. Wan, T. H. Wang, Contact-controlled sensing properties of flowerlike ZnO nanostructures, Applied Physics Letters 87 (2005) 213111.
[156] J. Garcıa Sole; L. E. Bausa; D. Jaque, An Introduction to the Optical Spectroscopy of Inorganic Solids; John Wiley & Sons, Ltd.: Chichester, U.K., 2005; Chapter 4, P124.
[157] Q. B. Ma, Z. Z. Ye, H. P. He, L. P. Zhu, J. Y. Huang, Y. Z. Zhang, B.H. Zhao, Influence of annealing temperature on the properties of transparent conductive and near-infrared reflective ZnO:Ga films, Scripta Materialia 58 (2008) 21.
[158] W. D. Munz, I. J. Smith, D. B. Lewis, S. Creasey, ZnO film formation using a steered and shielded reactive vacuum arc deposition, Vacuum 48 (1997) 473.
[159] H. W. Lee, S. P. Lau, Y. G. Wang, K. Y. Tse, H. H. Hng, B. K. Tay, Structural, electrical andoptical properties of Al-dopedZnO thin films preparedby filteredcathod ic vacuum arc technique, Journal of Crystal Growth 268 (2004) 596.
[160] M.-W. Wu, D.-S. Liu, Y.-H. Su, The densification, microstructure, and electrical properties of aluminum-doped zinc oxide sputtering target for transparent conductive oxide film, Journal of the European Ceramic Society 32 (2012) 3265.
[161] T. Miyata, Y. Minamino, S. Ida, T. Minami, Highly transparent and conductive ZnO:Al thin films prepared by vacuum arc plasma evaporation, Journal Vacuum Science & Technology A 22 (2004) 1711.
[162] J. S. Jeong, J. Y. Lee, J. H. Cho, C. J. Lee, S.-J. An, G.-C. Yi, R. Gronsky, Growth behaviour of well-aligned ZnO nanowires on a Si substrate at low temperature and their optical properties, Nanotechnology 16 (2005) 2455.
[163] E. Mirica, G. Kowach, P. Evans, H. Du, Morphological evolution of ZnO thin films deposited by reactive sputtering, Crystal Growth & Design 4 (2004) 147.
[164] G. C. A. M. Janssen, Stress and strain in polycrystalline thin films, Thin Solid Films 515 (2007) 6654.
[165] C. C. Hsiao, Y. C. Hu, R. C. Chang, C. K. Chao, Residual stresses and mechanical properties of a ZnO pyroelectric sensor, Theoretical and Applied Fracture Mechanics 52 (2009) 1.
[166] F. Conchon, P. O. Renault, E. Le Bourhis, C. Krauss, P. Goudeau, E. Barthel, S. Y. Grachev, E. Sondergard, V. Rondeau, R. Gy, R. Lazzari, J. Jupille, N. Brun, X-ray diffraction study of thermal stress relaxation in ZnO films deposited by magnetron sputtering, Thin Solid Films 519 (2010) 1563.
[167] Z. B. Bahsi, M. H. Aslan, M. Ozer, A.Y. Oral, Sintering behavior of ZnO:Al ceramics fabricated by sol-gel derived nanocrystalline powders, Crystal Research & Technology 44 (2009) 961.
[168] J. F. Chang, C. C. Shen, M. H. Hon, Growth characteristics and residual stress of RF magnetron sputtered ZnO:Al films, Ceramics International 29 (2003) 245.
[169] A. Bikowski, T. Welzel, K. Ellmer, The impact of negative oxygen ion bombardment on electronic and structural properties of magnetron sputtered ZnO:Al films, Applied Physics Letters 102 (2013) 242106.
[170] J. A. Chisholm, P. D. Bristowe, A first principles investigation of stacking fault energies and bonding in wurtzite materials, Journal of Physics: Condensed Matter 11 (1999) 5057.
[171] P. Zhang, X. Zheng, D. He, Kinetic Monte Carlo simulation of nucleation at the initial stage of thin film growth, Journal of the Korean Physical Society 46 (2005) S92.
[172] M. Pohler, R. Franz, J. Ramm, P. Polcik, C. Mitterer, Cathodic arc deposition of (Al,Cr)2O3: Macroparticles and cathode surface modifications, Surface & Coatings Technology 206 (2011) 1454.
[173] W.-J. Li, E.-W. Shi, W.-Z. Zhong, Z.-W. Yin,Growth mechanism and growth habit of oxide crystals, Journal of Crystal Growth 203 (1999) 186.
[174] K. Ellmer, R. Mientus, Carrier transport in polycrystalline transparent conductive oxides: A comparative study of zinc oxide and indium oxide, Thin Solid Films 516 (2008) 4620.