Synthesis and applications of ZnO nanostructure have been investigated. Based on the environmental concern and energy issue, ZnO-based nanostructures, fabricated by low-cost, large-scale aqueous method, have been applied to ethanol and CO gas sensing as well as light emitting diodes (LEDs). With applied voltage to aqueous solution, the impurity Co atoms have been effective to be doped into ZnO lattice. The cathodoluminescence (CL) peaks of different concentrations of Co-doped ZnO nanostructures are discussed. Meanwhile, high temperature ferromagnetism was observed in both 0.25% and 1% Co-doped ZnO nanostructures at 350 K.
Efforts have been made to the synthesis of ZnO-based nanostructures, understanding of its physical properties, and integration into potential devices in the research.
The thesis covers synthesis of ZnO-based nanostructures and its potential applications as fellow: (1) ZnO/ZnGa2O4 core-shell heterogeneous structure and ZnGa2O4 nanotubes, (2) unique hexagonal ring-like superstructures (HRLSs) based on the oriented attachment of single-crystalline Co-doped ZnO nanorods of hexagonal shape, (3) ZnO-based sensors applied to ethanol and CO sensing, (4) inorganic/organic heterostructure light emitting diodes consisting of ZnO-based nanorod and p-type polymer (PSS-PEDOT).

基於氧化鋅具有獨特的性質及多樣的奈米結構，本論文探討氧化鋅的合成。
近來環保及能源議題的重視日與劇增，利用低成本大面積的水熱法形成的氧化鋅奈米結構，也成功應用在酒精和一氧化碳的偵測，及發光二極體的元件製作。我們將水溶液外加電壓，有效的摻雜鈷原子進氧化鋅晶格內，也研究了不同的摻雜量對於陰極發光性質的影響。另外，發現摻雜0.25% and 1% 鈷的氧化鋅奈米結構，具有室溫鐵磁性(350K)。
本論文的主體為合成出不同的氧化鋅為主體的奈米結構，觀察探討其物理性質，製作成各種元件，並尋找更進一步的可能發展。
本論文包含了以下的氧化鋅相關奈米結構合成及潛力應用：(1)合成氧化鋅/四氧化二鎵鋅的核-殼奈米異質結構及四氧化二鎵鋅奈米管、(2)優選方向堆疊，單晶鈷摻雜六角環狀氧化鋅奈米線，自組裝成環狀結構、(3)氧化鋅相關奈米結構應用在酒精與一氧化碳氣體偵測、(4)氧化鋅奈米棒與p-型高分子組成的有機無機異質結構發光二極體。

Chapter 1
1.1 Zhong Lin Wang, Z. C. Kang, Functional and Smart Material, Plenum, New York 1998.
1.2 a) X. Y. Kong, Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts,” Nano Lett. 2003, 3, 1625-1631; b) P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. S. Lao, Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice-structured nanohelices,” Science, 2005, 309, 1700-1704.
1.3 P. X. Gao, Z. L. Wang, “Nanopropeller arrays of zinc oxide,” Appl. Phys. Lett. 2004, 84, 2883-2885.
1.4 R. C. Wang, C. P. Liu, J. L. Huang, S. J. Chen, Y. K. Tseng, S. C. Kung, “ZnO nanopencils: efficient field emitters,” Appl. Phys. Lett. 2005, 87, 013110.
1.5 Y. C. Chang, L. J. Chen, “ZnO nanoneedles with enhanced and sharp ultraviolet cathodoluminescence peak,” J. Phys. Chem. C 2007, 111, 1268-1272.
1.6 Jun Zhou, Ningsheng Xu, Zhong L. Wang, “Dissolving behavior and stability of ZnO wires in biofluids: a study on biodegradability and biocompatibility of ZnO nanostructures,” Adv. Mater. 2006, 18, 2432-2435.
1.7 a) Chang Shi Lao, Qin Kuang, Zhong L. Wang, “Polymer functionalized piezoelectric-FET as humidity/chemical nanosensors,” Appl. Phys. Lett. 2007, 90, 262107-1-262107-3. b) Chang Shi Lao, Myung-Chul Park, Qin Kuang, Yulin Deng, Ashok. K. Sood, Dennis L. Polla, Zhong L. Wang, “Giant enhancement in UV response of ZnO nanobelts by polymer surface-functionalization,” J. Am. Chem. Soc. 2007, 129, 12096-12097.
1.8 J. H. He, Yen H. Lin, Michael E. McConney, Vladimir V. Tsukruk, Zhong L. Wang, “Enhancing UV photoconductivity of ZnO nanobelt by polyacrylonitrile functionalization,” J. Appl. Phys. 2007, 102, 084303.
1.9 J. H. He, S. T. Ho, T. B. Wu, L. J. Chen, Z. L. Wang, “Electrical and photoelectrical performances of nano-photodiode based on ZnO nanowires,” Chem. Phys. Lett. 2007 435, 119-122.
1.10 Zhong Lin Wang, “The new field of nanopiezotronics,” Materialstoday 2007, 10, 20-28.
1.11 C. J. Humphreys, “Solid state lighting,” MRS Bulletin, 2008, 33, 459-470.
1.12 S. M. Sze, Semiconductor Devices: Physics and Technology, 1986, Ch.12.
1.13 S. Nakamura,“Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light emitting diodes,” Appl. Phys. Lett. 1994, 64, 1687-1689.
1.14 J. Goldberger, R. He, Y. Zhang, S. Lee, H. Yan, H. J. Choi, and P. Yang, “Single-crystal gallium nitride nanotubes,” Nature 2003, 422, 599-602.
1.15 M. C. Schlamp, X. Peng, and A. P. Alivisatos, “Improved efficiencies in light emitting diodes made with CdSe(CdS) core/shell type nanocrystals and a semiconducting polymer,” J. Appl. Phys. 1997, 82, 5837-5842.
1.16 O. Hayden, A. B. Greytak, and D. C. Bell, “Core-shell nanowire light-emitting diodes,” Adv. Mater. 2005, 17, 701-704.
1.17 C. Levy-Clement, R. Tena-Zaera, M. A. Ryan, A. Katty, and G. Hodes, “CdSe-Sensitized p-CuSCN/nanowire n-ZnO heterojunctions,” Adv. Mater. 2005, 17, 1512-1515.
1.18 Lincoln. J. Lauhon, Mark. S. Gudiksen, Deli. Wang, and Charles. M. Lieber, “Epitaxial core-shell and core-multishell nanowire heterostructures,” Nature 2002, 420, 57-61.
1.19 A. C. Jones and P. O’Brien, CVD of Compound Semiconductors: Precursor Synthesis, Development and Applications (VCH, Weinheim, 1997).
1.20 J. H. Wang, T. H. Yang, W. W. Wu, L. J. Chen, C. H. Chen, and C. J. Chiu, “Synthesis and growth mechanism of pentagonal Cu nanobats with field emission characteristics,” Nanotechnology 2006, 17, 719-722.
1.21 T. Omata, N. Ueda and H. Kawazoe, “New ultraviolet-transport electroconductive oxide, ZnGa2O4 spinel,” Appl. Phys. Lett. 1994, 64, 1077-1078.
1.22 J. S. Kim, H. I. Kang, W. N. Kim, J. I. Kim, J. C. Choi, H. L. Park, G. C. Kim, T. W. Kim, Y. H. Hwang, S. I. Mho, M. C. Jung, and M. Han, “Color variation of ZnGa2O4 phosphor by reduction-oxidation processes,” Appl. Phys. Lett. 2003, 82, 2029-2031.
1.23 L. E. Shea, R. K. Datta, and J. J. Brown, Jr, “Low-voltage cathodoluminescence of Mn2+-activated ZnGa2O4,” J. Electrochem. Soc. 1994, 141, 2198-2200.
1.24 J. H. Kim and P. H. Holloway, “Enhancement of cathodoluminescence of ZnGa2O4: Mn thin-film phosphor by energetic particle bombardment,” Appl. Phys. Lett. 2004, 84, 2070-2072.
1.25 Y. E. Lee, D. P. Norton, and J. D. Budai, “Enhanced photoluminescence in epitaxial ZnGa2O4 : Mn thin-film phosphors using pulsed-laser deposition,” Appl. Phys. Lett. 1999, 74, 3155-3157.
1.26 T. Minami, Y. Kuroi, T. Miyata. H, Yamada, and S. Takata, “ZnGa2O4 as host material for multicolor-emitting phosphor layer of electroluminescent devices,” J. Luminescence, 1997, 72, 997-998.
1.27 Heon-Jin Choi, Han-Kyu Seong, Joonyeon Chang, Kyeong-Il Lee, Young-Ju Park, Ju-Jin Kim, Sang-Kwon Lee, Rongrui He, Tevye Kuykendall, Peidong Yang, “Single-crystalline diluted magnetic semiconductor GaN:Mn nanowires,” Adv. Mater. 2005, 17, 1351-1356.
1.28 Jeong M. Bailk, and Jong-Lam Lee, “Fabrication of vertically well-aligned (Zn,Mn)O nanorods with room-temperature ferromagnetism,” Adv. Mater. 2005, 17, 2745-2748.
1.29 T. Dietl, H. Ohno, F. Matsukura, J. Cibert, and D. Ferrand, “Zener model description of ferromagnetism in zinc-blende magnetic semiconductors,” Science 2000, 287, 1019-1022.
1.30 R. S. Wagner, W. C. Ellis, “Vapor-solid-liquid mechanism of single crystal growth,” Appl. Phys. Lett. 1964, 4, 89-90.
1.31 a) X. Y. Kong, Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts,” Nano Lett. 2003, 3, 1625-1631; b) P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. S. Lao, Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice-structured nanohelices,” Science, 2005, 309, 1700-1704; c) J. H. He, J. H. Hsu, H. N. Lin, L. J. Chen, and Z. L. Wang, “Pattern and feature designed growth of ZnO nanowire arrays for vertical devices,” J. Phys. Chem. B 2006, 110, 50-53.
1.32 P. X. Gao, Z. L. Wang, “Nanopropeller arrays of zinc oxide,” Appl. Phys. Lett. 2004, 84, 2883-2885.
1.33 R. C. Wang, C. P. Liu, J. L. Huang, S.-J. Chen, Y. -K. Tseng, S. -C. Kung, “ZnO nanopencils: efficient field emitters,” Appl. Phys. Lett. 2005, 87, 013110.
1.34 a) J. H. He, C. S. Lao, L. J. Chen, D. Davidovic, and Z. L. Wang, “Large-scale Ni-doped ZnO nanowire arrays and electrical and optical Properties,” J. Am. Chem. Soc. 2005, 127, 16376-16377; b) J. H. He, C. L. Hsin, J. Liu, L. J. Chen, and Z. L. Wang, “Piezoelectric gated diode of a single ZnO nanowire,” Adv. Mater. 2007, 19, 781-784.
1.35 Y. C. Chang, L. J. Chen, “ZnO nanoneedles with enhanced and sharp ultraviolet cathodoluminescence peak,” J. Phys. Chem. C 2007, 111, 1268-1272.
1.36 L. Vayssieres, “Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions,” Adv. Mater. 2003, 15, 464-466.
1.37 Lionel Vayssieres, Karin Keis, Sten-Eric Lindquist, and Anders Hagfeldt, “Purpose-built anisotropic metal oxide material: 3D highly oriented microrod array of ZnO,” J. Phys. Chem. B 2001, 105, 3350-3352.
1.38 Feng Li, Yong Ding, Puxian Gao, Xinquan Xin, and Zhong L. Wang, “Single-crystal hexagonal disks and rings of ZnO: low-temperature, large-scale synthesis and growth mechanism,” Angew. Chem. 2004, 116, 5350-5354.
1.39 Zhuo Wang, Xue-feng Qian, Jie Yin, and Zi-kang Zhu, “Large-scale Fabrication of tower-like, flower-like and tube-like ZnO arrays by a simple chemical solution route,” Langmuir, 2004, 20, 3441-3448.
1.40 Lukas Schmidt-Mende and Judith L. MacManus-Driscoll, “ZnO-nanostructures, defects, and devics,” Materialstoday 2007, 5, 40-47.
1.41 J. B. Cui, and U. J. Gibon, “Electrodeposition and room temperature ferromagnetic anisotropy of Co and Ni-doped ZnO nanowire arrays,” Appl. Phys. Lett. 2005, 87, 133108.
1.42 D. H. Zhang, Z. Q. Liu, C. Li, T. Chang, X. L. Liu, S. Han, B. Lei, C. W. Zhou,“Detection of NO2 down to ppb Levels Using Individual and Multiple In2O3 Nanowire Devices,” NanO Lett. 2004, 4, 1919-1924.
1.43 Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, “Fabircaion and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 2004, 84, 3654-3656.
1.44 Sergiu T. Shishiyanu, Teodor S. Shishiyanu, Oleg I. Lupan, “Sensing characteristics of tin-doped ZnO thin film as NO2 gas sensor,” Sens. Actuators B 2005, 107, 379-386.
1.45 H. Gong, J. Q. Hu, J. H. Wang, C. H. Ong, F. R. Zhu, “Nano-crystalline Cu-doped ZnO thin film gas sensor for CO,” Sens. Actuators B 2006, 115, 247-251.
1.46 I. Stambolova, K. Konstantinov, S. Vassilev, P. Peshev, Ts. Tsacheva, “Lanthanum doped SnO2 and ZnO thin films sensitive to ethanol and humidity,” Mater. Chem. Phys. 2000, 63, 104-108.
1.47 F. Paraguay D., M. MiKi-Yoshida, J. Morales, J. Solis, W. Estrada L. “Influence of Al, In, Cu, Fe and Sn dopants on the response of thin film ZnO gas sensor to ethanol vapour,” Thin Solid Films 2000, 373, 137-140.
1.48 Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, “Fabircaion and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 2004, 84, 3654-3656.
1.49 Andrei Kolmakov, Martin Moskovits, “Chemical sensing and catalysis by one-dimensional metal-oxide nanostructures,” Annu. Rev. Mater. Res. 2004, 34, 151-180.
1.50 R. Kőnenkamp, Robert C. Word, and C. Schlegel, “Vertical nanowire light-emitting diode,” Appl. Phys. Lett. 2004, 85, 6004-6006.
1.51 Atsushi Tsukazaki, Akira Ohtomo, Takeyoshi Onuma, Makoto Ohtani, Takayuki Makino, Masatomo Sumiya, Keita Ohtani, Shigefusa F. Chichibu, Syunrou Fuke,Yusaburou Segawa, Hideo Ohno, Hideomi Koinuma, and Masashi Kawasaki, “Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO,” Nature Materials 2005, 4, 42-46.
1.52 R. Kőnenkamp, Robert C. Word, and M. Godinez, “Ultraviolet electroluminescence from ZnO/polymer heterojunction light-emitting diodes,” Nano Lett. 2005, 5, 2005-2008.
1.53 Jiming Bao, Mariano A. Zimmler, and Federico Capasso, “Broadband ZnO single-nanowire light-emitting diode,” Nano Lett. 2006, 6, 1719-1722.
1.54 Athavan Nadarajah, Robert C. Word, Jan Meiss, and Rolf Kőnenkamp, “Flexible inorganic nanowire light-emitting diode,” Nano Lett. 2008, 8, 534-547.
1.55 X. W. Sun, J. Z. Huang, J. X. Wang, and Z. Xu, “A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm,” Nano Lett. 2008, 8, 1219-1223.

Chapter 3

3.1 J. Goldberger, R. He, Y. Zhang, S. Lee, H. Yan, H.J. Choi, and P. Yang, “Single-crystal gallium nitride nanotubes,” Nature 2003, 422, 599-602.
3.2 M. C. Schlamp, X. Peng, and A. P. Alivisatos, “Improved efficiencies in light emitting diodes made with CdSe(CdS) core/shell type nanocrystals and a semiconducting polymer,” J. Appl. Phys. 1997, 82, 5837-5842.
3.3 O. Hayden, A. B. Greytak, and D. C. Bell, “Core-shell nanowire light-emitting diodes,” Adv. Mater. 2005, 17, 701-704.
3.4 C. Levy-Clement, R. Tena-Zaera, M. A. Ryan, A. Katty, and G. Hodes, “CdSe-Sensitized p-CuSCN/nanowire n-ZnO heterojunctions,” Adv. Mater. 2005, 17, 1512-1515.
3.5 Lincoln. J. Lauhon, Mark. S. Gudiksen, Deli. Wang, and Charles. M. Lieber, “Epitaxial core-shell and core-multishell nanowire heterostructures,” Nature 2002, 420, 57-61.
3.6 A. C. Jones and P. O’Brien, CVD of Compound Semiconductors: Precursor Synthesis, Development and Applications (VCH, Weinheim, 1997).
3.7 J. H. Wang, T. H. Yang, W. W. Wu, L. J. Chen, C. H. Chen, and C. J. Chiu, “Synthesis and growth mechanism of pentagonal Cu nanobats with field emission characteristics,” Nanotechnology 2006, 17, 719-722.
3.8 T. Omata, N. Ueda and H. Kawazoe, “New ultraviolet-transport electroconductive oxide, ZnGa2O4 spinel,” Appl. Phys. Lett. 1994, 64, 1077-1078.
3.9 J. S. Kim, H. I. Kang, W. N. Kim, J. I. Kim, J. C. Choi, H. L. Park, G. C. Kim, T. W. Kim, Y. H. Hwang, S. I. Mho, M. C. Jung, and M. Han, “Color variation of ZnGa2O4 phosphor by reduction-oxidation processes,” Appl. Phys. Lett. 2003, 82, 2029-2031.
3.10 L. E. Shea, R. K. Datta, and J. J. Brown, Jr, “Low-voltage cathodoluminescence of Mn2+-activated ZnGa2O4,” J. Electrochem. Soc. 1994, 141, 2198-2200.
3.11 J. H. Kim and P. H. Holloway, “Enhancement of cathodoluminescence of ZnGa2O4: Mn thin-film phosphor by energetic particle bombardment,” Appl. Phys. Lett. 2004, 84, 2070-2072.
3.12 Y. E. Lee, D. P. Norton, and J. D. Budai, “Enhanced photoluminescence in epitaxial ZnGa2O4 : Mn thin-film phosphors using pulsed-laser deposition,” Appl. Phys. Lett. 1999, 74, 3155-3157.
3.13 T. Minami, Y. Kuroi, T. Miyata. H, Yamada, and S. Takata, “ZnGa2O4 as host material for multicolor-emitting phosphor layer of electroluminescent devices,” J. Luminescence, 1997, 72, 997-998.
3.14 S. Y. Bae, H. W. Seo, C. W. Na, and J. H. Park, “Synthesis of blue-emitting ZnGa2O4 nanowires using chemical vapor deposition,” Chem. Commun. 2004, 16, 1834-1835.
3.15 J. Hu, Y. Bando, and Z. Liu, “Synthesis of gallium-filled gallium oxide-zinc oxide composite coaxial nanotubes,” Adv. Mater. 2003, 15, 1000-1003.
3.16 J. H. He, C. S. Lao, L. J. Chen, D. Davidovic, and Z. L. Wang, “Large-scale Ni-doped ZnO nanowire arrays and electrical and optical properties,” J. Am. Chem. Soc. 2005, 127, 16376-16378.
3.17 H. Maki, T. Ikoma, I. Sakaguchi, N. Ohashi, H. Haneda, J. Tanaka, and H. Ichinose, “Control of surface morphology of ZnO ( ) by hydrochloric acid etching,” Thin Solid Films 2002, 411, 91-95.
3.18 J. Zhu, N. W. Emanetoglu, Y. Chen, B. V. Yakshinskiy, and Y. Lu, “Wet-chemical etching of ( ) ZnO films,” J. Electronic Mate. 2004, 33, 556-559.
3.19 Y. D. Li, X. F. Duan, H. W. Liao, and Y. T. Qian, “Self-regulation synthesis of nanocrystalline ZnGa2O4 by hydrothermal reaction,” Chem. Mater. 1998, 10, 17-18.
3.20 F. Ren, M. Hong, J. P. Mannaerts, J. R. Lothian, and A. Y. Cho, “Wet chemical and plasma etching of Ga2O3 (Gd2O3),” J. Electrochem. Soc. 1997, 144, L239-L241.
3.21 C. W. W. Hoffman and J. J. J. Brown, “Compound formation and Mn2+-activated luminescence in binary systems R2O- and RO-Ga2O3,” Inorg. Nucl..Chem. 1968, 30, 63-79.
3.22 K.Vanhausden, W. L. Warren, C. H. Seager, D. R. Tallant, J. A. Voigt, and B. E. Gnade, “Mechanisms behind green photoluminescence in ZnO phosphor powders,” J. Appl. Phys. 1996, 79, 7983-7990.
3.23 C. H. Hsu, Y. R. Lin, S. J. Chang, T. S. Lin, S. Y. Tsai, and I. C. Chen, “Vertical ZnO/ZnGa2O4 core-shell nanorods grown on ZnO/glass templates by reactive evaporation,” Chem. Phys. Lett. 2005, 41, 221-224.
3.24 I. K. Jeong, H. L. Park, and S. I. Mho, “Two self-activated optical centers of blue emission in zinc gallate,” Solid State Commun. 1998, 105, 179-183.
3.25 P. C. Chang, Z. Fan, D. Wang, W. Y. Tseng, W. A. Chiou, J. Hong, and J. G. Liu, “ZnO nanowires synthesized by vapor trapping CVD method,” Chem. Mater. 2004, 16, 5133-5137.
3.26 C. F. Yu, and P. Lin. “Manganese-activated luminescence in ZnGa2O4,” J. Appl. Phys. 1996, 79, 7191-7197.
3.27 Y. E. Lee, D. P. Norton, C. Park, and C. M. Rouleau, “Blue photoluminescence in ZnGa2O4 thin-film phosphors,” J. Appl. Phys. 2001, 89, 1653-1656.
3.28 K. W. Chang and J. J. Wu, “Formation of well-aligned ZnGa2O4 nanowires from Ga2O3/ZnO core-shell nanowires via a Ga2O3/ZnGa2O4 epitaxial relationship,” J. Phys. Chem. B 2005, 109, 13572-13577.

Chapter 4
4.1 X. Y. Kong, Y. Ding, R. Yang, Z. L. Wang, “Single-crystal nanorings formed by epitaxial self-coiling of polar nanobelts,” Science 2004, 303, 1348-1351.
4.2 Feng Li, Yong Ding, Puxian Gao, Xinquan Xin, and Zhong L. Wang, “Single-crystal hexagonal disks and rings of ZnO: low-temperature, large-scale synthesis and growth mechanism,” Angew. Chem. 2004, 116, 5350-5354.
4.3 F. Yan, W. A. Goedel, “The preparation of mesoscopic rings in collidal crystal templates,” Angew. Chem. Int. Ed. 2005, 44, 2084-2088.
4.4 a) G. Lu, W. Li, J. M. Yao, G. Zhang, B. Yang, J. C. Shen, “Fabricating ordered two-dimensional arrays of polymer rings with submicrometer-sized features on patterned self-assembled monolayers by dewetting,” Adv. Mater. 2002, 14, 1049-1053; b) J. K. Kim, E. Lee, Z. Huang, M. Lee, “Nanorings from the self-assembly of amphiphilic molecular dumbbells,” J. Am. Chem. Soc. 2006, 128, 14022-14023.
4.5 S. L. Tripp, R. Dunin-Borkowski, A. Wei, “Flux closure in self-assembled cobalt nanoparticle rings,” Angew. Chem. Int. Ed. 2003, 42, 5591-5593.
4.6 a) Bin Liu, and Hua Chun Zeng, “Semiconductor rings fabrication by self-assembly of nanocrystals,” J. Am. Chem. Soc. 2005, 127, 18262-18268; b) Bishnu P. Khanal and Eugene R. Zubarev, “Rings of nanorods,” Angew. Chem. Int. Ed. 2007, 46, 2195-2198.
4.7 Heon-Jin Choi, Han-Kyu Seong, Joonyeon Chang, Kyeong-Il Lee, Young-Ju Park, Ju-Jin Kim, Sang-Kwon Lee, Rongrui He, Tevye Kuykendall, Peidong Yang, “Single-crystalline diluted magnetic semiconductor GaN:Mn nanowires,” Adv. Mater. 2005, 17, 1351-1356.
4.8 Jeong M. Bailk, and Jong-Lam Lee, “Fabrication of vertically well-aligned (Zn,Mn)O nanorods with room-temperature ferromagnetism,” Adv. Mater. 2005, 17, 2745-2748.
4.9 T. Dietl, H. Ohno, F. Matsukura, J. Cibert, and D. Ferrand, “Zener model description of ferromagnetism in zinc-blende magnetic semiconductors,” Science 2000, 287, 1019-1022.
4.10 J. B. Cui, and U. J. Gibon, “Electrodeposition and room temperature ferromagnetic anisotropy of Co and Ni-doped ZnO nanowire arrays,” Appl. Phys. Lett. 2005, 87, 133108.
4.11 T. Omata, N. Ueda and H. Kawazoe, “New ultraviolet-transport electroconductive oxide, ZnGa2O4 spinel,” Appl. Phys. Lett. 1994, 64, 1077-1078.
4.12 Y. J. Li, M. Y. Lu, C. W. Wang, K. M. Li, and L. J. Chen, “ZnGa2O4 nanotubes with sharp cathodoluminescence peak,” Appl. Phys. Lett. 2006, 88, 143102.
4.13 a) X. Y. Kong, Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts,” Nano Lett. 2003, 3, 1625-1631; b) P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. S. Lao, Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice-structured nanohelices,” Science, 2005, 309, 1700-1704; c) J. H. He, J. H. Hsu, H. N. Lin, L. J. Chen, and Z. L. Wang, “Pattern and feature designed growth of ZnO nanowire arrays for vertical devices,” J. Phys. Chem. B 2006, 110, 50-53.
4.14 P. X. Gao, Z. L. Wang, “Nanopropeller arrays of zinc oxide,” Appl. Phys. Lett. 2004, 84, 2883-2885.
4.15 R. C. Wang, C. P. Liu, J. L. Huang, S.-J. Chen, Y. -K. Tseng, S. -C. Kung, “ZnO nanopencils: efficient field emitters,” Appl. Phys. Lett. 2005, 87, 013110.
4.16 Y. C. Chang, L. J. Chen, “ZnO nanoneedles with enhanced and sharp ultraviolet cathodoluminescence peak,” J. Phys. Chem. C 2007, 111, 1268-1272.
4.17 a) J. H. He, C. S. Lao, L. J. Chen, D. Davidovic, and Z. L. Wang, “Large-scale Ni-doped ZnO nanowire arrays and electrical and optical Properties,” J. Am. Chem. Soc. 2005, 127, 16376-16377; b) J. H. He, C. L. Hsin, J. Liu, L. J. Chen, and Z. L. Wang, “Piezoelectric gated diode of a single ZnO nanowire,” Adv. Mater. 2007, 19, 781-784.
4.18 L. Vayssieres, “Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions,” Adv. Mater. 2003, 15, 464-466.
4.19 Lionel Vayssieres, Karin Keis, Sten-Eric Lindquist, and Anders Hagfeldt, “Purpose-built anisotropic metal oxide material: 3D highly oriented microrod array of ZnO,” J. Phys. Chem. B 2001, 105, 3350-3352.
4.20 Zhuo Wang, Xue-feng Qian, Jie Yin, and Zi-kang Zhu, “Large-scale fabrication of tower-like, flower-like and tube-like ZnO arrays by a simple chemical solution route,” Langmuir, 2004, 20, 3441-3448.
4.21 T. Akasaka, Y. Kobayashi, S. Ando, and N. Kobayashi, “GaN hexagonal microprisms with smooth vertical facets fabricated by selective metalorganic vapor phase epitaxy,” Appl. Phys. Lett. 1997, 71, 2196-2198.
4.22 R. Lee Penn, and Jillian F. Banfied, “Imperfect oriented attachment: Dislocation generation in defect-free nanocrystals,” Science 1998, 281, 969-971.
4.23 R. Lee Penn, “Kinetics of oriented aggregation,” J. Phys. Chem. B 2004, 108, 12707-12712.
4.24 A. C. Tuan, J. D. Bryan, A. B. Pakhomov, V. Shutthanandan, S. Thevuthasan, D. E. McCready, D. Gaspar, M. H. Engelhard, J. W. Rogers, Jr., K. Krishnan, D. R. Gamelin, and S. A. Chambers, “Epitaxial growth and properties of cobalt-doped ZnO on alpha-Al2O3 single-crystal substrates,” Phys. Rev. B 2004, 70, 054424.
4.25 Y. Q. Chang, D. B. Wang, X. H. Luo, X. Y. Xu, X. H. Chen, L. Li, C. P. Chen, R. M. Wang, J. Xu, D. P. Yu, “Synthesis, optical, and magnetic properties of diluted magnetic semiconductor Zn1-xMnxO nanowires via vapor phase growth,” Appl. Phys. Lett. 2003, 83, 4020-4022.
4.26 A. B. Djurišic, W. C. H. Choy, V. A. L. Roy, Y. H. Leung, C. Y. Kwong, K. W. Cheah, T. K. Gundu Rao, W. K. Chan, H. Fei Lui, C. Surya, “Photoluminescence and electron paramagnetic resonance of ZnO tetrapod structures,” Adv. Funct. Mater. 2004, 14, 856-864.
4.27 Kwang Joo Kim, and Young Ran Park, “Spectroscopic ellipsometry study of optical transitions in Zn1-xCoxO alloys,” Appl. Phys. Lett. 2002, 81, 1420-1422.
4.28 K Sato and H Katayama-Yoshida, “First principles materials design for semiconductor spintronics,” Semicon. Sci. Technol. 2002, 17, 367-376.
4.29 N. Khare, M. J. Kappers, M. Wei., M. G. Blamire, and J. L. MacManus-Driscoll, “Defect-induced ferromagnetism in co-doped ZnO,” Adv. Mater. 2006, 18, 1449-1452.

Chapter 5
5.1 Victor V. Sysoev, Bradly K. Button, Kelly Wepsiec, Serghei Dmitriev, Andrei Kolmakov, “Toward the nanoscopic “electronic nose”: hydrogen vs carbon monoxide discrimination with an array of individual metal oxide nano- and mesowire sensors,” Nano Lett. 2006, 6, 1584-1588.
5.2 Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, “Fabircaion and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 2004, 84, 3654-3656.
5.3 P. Feng, Q. Wan, T. H. Wang, “Contact-controlled sensing properties of flowerlike ZnO nanostructures,” Appl. Phys. Lett. 2005, 87, 213111.
5.4 Ting-Jen Hsueh, Shoou-Jinn Chang, “Highly sensitive ZnO nanowire ethanol sensor with Pd adsorption,” Appl. Phys. Lett. 2007, 91, 053111.
5.5 L. Liao, H. B. Lu, J. C. Li, C. Liu, and D. J. Fu, Y. L. Liu, “The sensitivity of gas sensor based on single ZnO nanowire modulated by helium ion radiation,” Appl. Phys. Lett. 2007, 91, 173110.
5.6 H. T. Wang, B. S. Kang, F. Ren, “Hydrogen-selective sensing at room temperature with ZnO nanorods,” Appl. Phys. Lett. 2005, 86, 243503.
5.7 Qin Kuang, Changshi Lao, Zhong Lin Wang, Zhaoxiong Xie, Lansun Zheng, “High-sensitivity humidity sensor based on a single SnO2 nanowire,” J. Am. Chem. Soc. 2007, 129, 6070-6071.
5.8 K. M. Li, Y. J. Li, M. Y. Lu, C. Y. Kuo, L. J. Chen, “Direct conversion of single-layer SnO nanoplates to multi-layer SnO2 nanoplates with enhanced ethanol sensing properties,” Adv. Funct. Mater. 2009, 19, 2453-2456.
5.9 Andrei Kolmakov, D. O. Klenov, Y. Liach, M. Moskovits, “Enhanced gas sensing by individual SnO2 nanowires and nanobelts functionalized with Pd catalyst particles,” Nano Lett. 2005, 5, 667-673.
5.10 Andrei Kolmakov, Martin Moskovits, “Chemical sensing and catalysis by one-dimensional metal-oxide nanostructures,” Annu. Rev. Mater. Res. 2004, 34, 151-180.
5.11 Jun Zhou, Ningsheng Xu, Zhong L. Wang, “Dissolving behavior and stability of ZnO wires in biofluids: a study on biodegradability and biocompatibility of ZnO nanostructures,” Adv. Mater. 2006, 18, 2432-2435.
5.12 a) Chang Shi Lao, Qin Kuang, Zhong L. Wang, “Polymer functionalized piezoelectric-FET as humidity/chemical nanosensors,” Appl. Phys. Lett. 2007, 90, 262107-1-262107-3. b) Chang Shi Lao, Myung-Chul Park, Qin Kuang, Yulin Deng, Ashok. K. Sood, Dennis L.Polla, Zhong L. Wang, “Giant enhancement in UV response of ZnO nanobelts by polymer surface-functionalization,” J. Am. Chem. Soc. 2007, 129, 12096-12097.
5.13 J. H. He, Yen H. Lin, Michael E. McConney, Vladimir V. Tsukruk, Zhong L. Wang, “Enhancing UV photoconductivity of ZnO nanobelt by polyacrylonitrile functionalization,” J. Appl. Phys. 2007, 102, 084303.
5.14 J. H. He, S. T. Ho, T. B. Wu, L. J. Chen, Z. L. Wang, “Electrical and photoelectrical performances of nano-photodiode based on ZnO nanowires,” Chem. Phys. Lett. 2007 435, 119-122.
5.15 Sergiu T. Shishiyanu, Teodor S. Shishiyanu, Oleg I. Lupan, “Sensing characteristics of tin-doped ZnO thin film as NO2 gas sensor,” Sens. Actuators B 2005, 107, 379-386.
5.16 H. Gong, J. Q. Hu, J. H. Wang, C. H. Ong, F. R. Zhu, “Nano-crystalline Cu-doped ZnO thin film gas sensor for CO,” Sens. Actuators B 2006, 115, 247-251.
5.17 I. Stambolova, K. Konstantinov, S. Vassilev, P. Peshev, Ts. Tsacheva, “Lanthanum doped SnO2 and ZnO thin films sensitive to ethanol and humidity,” Mater. Chem. Phys. 2000, 63, 104-108.
5.18 F. Paraguay D., M. MiKi-Yoshida, J. Morales, J. Solis, W. Estrada L. “Influence of Al, In, Cu, Fe and Sn dopants on the response of thin film ZnO gas sensor to ethanol vapour,” Thin Solid Films 2000, 373, 137-140.
5.19 X. Y. Kong, Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts,” Nano Lett. 2003, 3, 1625-1631.
5.20 P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. S. Lao, Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice-structured nanohelices,” Science 2005, 309, 1700-1704.
5.21 P. X. Gao, Z. L. Wang, “Nanopropeller arrays of zinc oxide,” Appl. Phys. Lett. 2004, 84, 2883-2885.
5.22 a) R. C. Wang, C. P. Liu, J. L. Huang, S.-J. Chen, Y. -K. Tseng, S. -C. Kung, “ZnO nanopencil: efficient field emitters,” Appl. Phys. Lett. 2005, 87, 013110. b) Ruey-Chi Wang, Chuan-Pu Liu, Jow-Lay Huang, Shu-Jen Chen, “ZnO symmetric nanosheets integrated with nanowells,” Appl. Phys. Lett. 2005, 87, 053103.
5.23 a) J. H. He, C. L. Hsin, J. Liu, L. J. Chen, and Z. L. Wang, “Piezoelectric gated diode of a single ZnO nanowire,” Adv. Mater. 2007, 19, 781-784. b) Jr H. He, Chang S. Lao, Lih J. Chen, Dragomir Davidovic, and Zhong L. Wang, “Large-scale Ni-doped ZnO nanowire arrays and electrical and optical Properties,” J. Am. Chem. Soc. 2005, 127, 16376-16377.
5.24 M. P. Lu, J. H. Song, M. Y. Lu, M. T. Chen, Y. F. Gao, L. J. Chen, and Z. L. Wang, “Piezoelectric nanogenerator using p-type ZnO nanowire arrays,” Nano Lett. 2009, 9, 1223-1227.
5.25 a) Lionel Vayssieres, “Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions,” Adv. Mater. 2003, 15, 464-466. b) Lionel Vayssieres, Karin Keis, Sten-Eric Lindquist, and Anders Hagfeldt, “Purpose-built anisotropic metal oxide material: 3D highly oriented microrod array of ZnO,” J. Phys. Chem. B 2001, 105, 3350-3352.
5.26 Feng Li, Yong Ding, Puxian Gao, Xinquan Xin, Zhong L. Wang, “Single-crystal hexagonal disks and rings of ZnO: low-temperature, large-scale synthesis and growth mechanism,” Angew. Chem. 2004, 116, 5350-5354.
5.27 Zhuo Wang, Xue-feng Qian, Jie Yin, Zi-kang Zhu, “Large-scale fabrication of tower-like, flower-like and tube-like ZnO arrays by a simple chemical solution route,” Langmuir 2004, 20, 3441-3448.
5.28 Y. C. Chang, L. J, Chen, “ZnO nanoneedles with enhanced and sharp ultraviolet cathodoluminescence peak,” J. Phys. Chem. C 2007, 111, 1268-1272.
5.29 Y. C. Chang, W. C. Yang, C. M. Chang, P. C. Hsu, L. J. Chen, “Controlled growth of ZnO nanopagoda arrays with varied lamination and apex angles,” Crystal Growth ＆ Design 2009, 9, 3161-3167.
5.30 J. B. Cui, U. J. Gibson, “Electrodeposition and room temperature ferromagnetic anisotropy of Co and Ni-doped ZnO nanowire arrays,” Appl. Phys. Lett. 2005, 87, 133108.
5.31 Y. J. Li, C. Y. Wang, M. Y. Liu, K. M. Li, L. J. Chen, “Electrodeposited hexagonal ring-like superstructures composed of hexagonal Co-doped ZnO nanorods with optical tuning and high-temperature ferromagnetic properties,” Crystal Growth ＆ Design 2008, 8, 2598-2602.
5.32 J. Y. Yu, G. M. Choi, “Electrical and CO gas sensing properties of ZnO-SnO2 composites,” Sens. Actuators B 1998, 52, 251-256.

Chapter 6
6.1 Chang Shi Lao, Myung-Chul Park, Qin Kuang, Yulin Deng, Ashok. K. Sood, Dennis L. Polla, and Zhong L. Wang, “Giant enhancement in UV response of ZnO nanobelts by polymer surface-functionalization,” J. Am. Chem. Soc. 2007, 129, 12096-2097.
6.2 J. H. He, Yen H. Lin, Michael E. McConney, Vladimir V. Tsukruk, and Zhong L. Wang, “Enhancing UV photoconductivity of ZnO nanobelt by polyacrylonitrile functionalization,” J. Appl. Phys. 2007, 102, 084303.
6.3 R. Kőnenkamp, Robert C. Word, and C. Schlegel, “Vertical nanowire light-emitting diode,” Appl. Phys. Lett. 2004, 85, 6004-6006.
6.4 Atsushi Tsukazaki, Akira Ohtomo, Takeyoshi Onuma, Makoto Ohtani, Takayuki Makino, Masatomo Sumiya, Keita Ohtani, Shigefusa F. Chichibu, Syunrou Fuke, Yusaburou Segawa, Hideo Ohno, Hideomi Koinuma, and Masashi Kawasaki, “Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO,” Nature Materials 2005, 4, 42-46.
6.5 R. Kőnenkamp, Robert C. Word, and M. Godinez, “Ultraviolet electroluminescence from ZnO/polymer heterojunction light-emitting diodes,” Nano Lett. 2005, 5, 2005-2008.
6.6 Jiming Bao, Mariano A. Zimmler, and Federico Capasso, “Broadband ZnO single-nanowire light-emitting diode,” Nano Lett. 2006, 6, 1719-1722.
6.7 Athavan Nadarajah, Robert C. Word, Jan Meiss, and Rolf Kőnenkamp, “Flexible inorganic nanowire light-emitting diode,” Nano Lett. 2008, 8, 534-547.
6.8 X. W. Sun, J. Z. Huang, J. X. Wang, and Z. Xu, “A ZnO nanorod inorganic/organic heterostructure light-emitting diode emitting at 342 nm,” Nano Lett. 2008, 8, 1219-1223.
6.9 C. J. Humphreys, “Solid state lighting,” MRS Bulletin, 2008, 33, 459-470.
6.10 Yi Jing Li, C. Y. Wang, M. Y. Liu, K. M. Li, and L. J. Chen, “Electrodeposited hexagonal ring-like superstructures composed of hexagonal Co-doped ZnO nanorods with optical tuning and high-temperature ferromagnetic properties,” Crystal Growth ＆ Design 2008, 8, 2598-2602.
6.11 Yi-Jing Li, Kun-Mu Li, and Lih-Juann Chen, unpolished work.
6.12 X. Y. Kong, Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts,” Nano Lett. 2003, 3, 1625-1631.
6.13 P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. S. Lao, Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice-structured nanohelices,” Science 2005, 309, 1700-1704.
6.14 Jr H. He, Chang S. Lao, Lih J. Chen, Dragomir Davidovic, and Zhong L. Wang, “Large-scale Ni-doped ZnO nanowire arrays and electrical and optical properties,” J. Am. Chem. Soc. 2005, 127, 16376-16377.
6.15 Y. J. Li, M. Y. Lu, C. W. Wang, K. M. Li, and L. J. Chen, “ZnGa2O4 nanotubes with sharp cathodoluminescence peak,” Appl. Phys. Lett. 2006, 88, 143102.
6.16 Lionel Vayssieres, “Growth of arrayed nanorods and nanowires of ZnO from aqueous solutions,” Adv. Mater. 2003, 15, 464-466.
6.17 Feng Li, Yong Ding, Puxian Gao, Xinquan Xin, and Zhong L. Wang, “Single-crystal hexagonal disks and rings of ZnO: low-temperature, large-scale synthesis and growth mechanism,” Angew. Chem. 2004, 116, 5350-5354.
6.18 Yu C. Chang, and L. J, Chen, “ZnO nanoneedles with enhanced and sharp ultraviolet cathodoluminescence peak,” J. Phys. Chem. C 2007, 111,1268-1272.
6.19 Min-Chang Jeong, Byeong-Yun Oh, Moon-Ho Ham, and Jae-Min Myoung, “Electroluminescence from ZnO nanowires in n-ZnO film/ZnO nanowire array/p-GaN film heterojunction light-emitting diodes ,” Appl. Phys. Lett. 2006, 88, 202105.

Chapter 8

8.1 M. Law, L. E. Greene, J. C. Johnson, R. Saykally, P. D. Yang, “Nanowire dye-sensitized solar cells,” Nature Materials, 2005, 4, 455-459.
8.2 Jason B. Baxter and Eray S. Aydil, “Nanowire-based dye-sensitized solar cells,” Appl. Phys. Lett. 2005, 86, 053114.
8.3 Matt Law, Lori E. Greene, Aleksandra Radenovic, Tevye Kuykendall, Jan Liphardt, and Peidong Yang, “ZnO−Al2O3 and ZnO−TiO2 core−shell nanowire dye-sensitized solar cells,” J. Phys. Chem. B, 2006, 110, 22652-22663.