Abstract

Among semiconductor materials, zinc oxide is one of the most important materials and has attracted much interest in recent years, due to its unique optical, electrical, magnetic and piezoelectric properties and versatile applications. Fabrication of n-type, p-type and p-n homojunction ZnO nanowires (NWs) was developed by using a vapor transport and condensation method without Au as catalyst. ZnO-coated Si wafer was used as a substrate for the growth of n-type, p-type and p-n homojunction ZnO nanowires. For p-type ZnO nanowires, the phosphorus-doped ZnO nanowires were grown on ZnO-coated substrate using zinc phosphide (Zn3P2) as the dopant source. Single-crystal intrinsic ZnO and P-doped ZnO nanowires have the growth axis along the [001] direction and are vertically-aligned on Si substrates. Furthermore, single-NW-based field-effect transistors (FETs) were used to study the electrical transport properties of the ZnO NWs.
Using phosphorus doped ZnO nanowire arrays grown on silicon substrate, energy conversion using the p-type ZnO NWs has been demonstrated for the first time. The p-type ZnO NWs produce positive piezoelectric output voltage pulses when scanned by a conductive AFM in contact mode. The output voltage peaks are as high as 50-90 mV for NWs with ~150 nm in diameter and 3-4 μm in length. The output voltage pulse is generated when the tip contacts the stretched side (positive piezoelectric potential side) of the NW. In contrast, the n-type ZnO NW produces negative piezoelectric output voltage when subjected to AFM deformation. On the other hand, the output voltage pulse is generated when the tip contacts the compressed side (negative potential side) of the NW. These experimentally observed phenomena have been systematically explained based on the mechanism proposed for nanogenerator.
Catalyst-free p-n homojunction ZnO nanowire (NW) arrays, in which the phosphorous (P) and zinc (Zn) served as p- and n-type dopants, respectively, have been synthesized for the first time by a controlled in-situ doping process for fabricating efficient ultraviolet light emitting devices. The doping transition region defined as the width for P atoms gradually occupying Zn sites along the growth direction can be narrowed down to sub-50 nm. The cathodoluminescence emission peak at 340 nm emitted from n-type ZnO:Zn NW arrays is likely due to the Burstein-Moss effect in the high electron carrier concentration regime. Further, the electroluminescence spectra from the p-n ZnO NW arrays distinctively exhibit the short-wavelength emission at 342 nm and the blue-shift from 342 nm to 325 nm is observed as the operating voltage further increasing. The ZnO NW p-n homojunctions comprising p-type segment with high electron concentration are promising building blocks for short-wavelength lighting device and photoelectronics.

摘要

氧化鋅由於具備獨特的光、電、磁以及壓電特性並且具有廣泛的應用性,因此是所有半導體材料中備受矚目的材料之一，因而在近幾年吸引了相當廣泛的研究。由於不同型態、維度及尺寸的氧化鋅具有其不同的性質及應用面，所以如何設計及控制氧化鋅奈米結構的成長便成了研究學者們的重點。n型、p型以及p-n同質接面氧化鋅奈米線是經由氣相沉積的方式來製備，其中成長過程不需藉由金當作催化劑。n型、p型以及p-n同質接面氧化鋅奈米線於已沈積氧化鋅作為核種之矽基板上成長。對於p型氧化鋅奈米線的製備，是以磷化鋅作為摻雜物並均勻的摻雜到氧化鋅奈米線內。合成出來的本質性氧化鋅及磷摻雜氧化鋅為單晶結構且均直立於矽基板上並沿著[001]方向成長。此外，藉由量測單根奈米線之場效應電晶體，進一步探討所合成之奈米線的電傳導性質。
利用成長於矽基材上之磷摻雜氧化鋅奈米線,第一次證實此p型氧化鋅奈米線能夠產生能量轉換效應。藉由一個導電性的AFM探針以接觸模式來掃掠p型氧化鋅奈米線，並且產生正向壓電輸出電壓脈衝。對於一片長滿直徑為150 nm且長度為3-4 μm之奈米線所產生的輸出電壓高達50-90 mV。當AFM探針接觸奈米線的伸展面時(正向壓電電位面)，就會產生正電壓輸出脈衝。相對的，當n型氧化鋅奈米線經由AFM探針接觸而產生變形時，會產生負向壓電輸出電壓；此電壓輸出脈衝是由於探針觸接奈米線的壓縮面(負向壓電電位面)所產生的。這些實驗上所觀察到的現象可依據奈米發電機相關而加以解釋。
p-n均質接面的氧化鋅奈米線陣列分別以磷(P)及鋅(Zn)作為p型及n型摻雜物、不需藉由催化劑並且第一次成功地藉由可控制同步摻雜過程來合成，並且製備成紫外光LED元件。摻雜的過渡區域被定義為磷原子沿著奈米線的成長方向逐漸地佔據鋅原子位置之寬度，其中此過渡區域的寬度可以縮小至50 nm以內。從n型ZnO: Zn奈米線陣列中所放出340 nm的CL放射光，可能是在高電子載子濃度區域內由於Burstein-Moss效應而所放出來的光。此外，從p-n氧化鋅奈米線陣列所量測到的EL光譜圖明顯地顯示在342 nm附近接收到一個短波長放光，隨著操作電壓的增加，此放光波長明顯地會從342 nm藍位移到325 nm。合成一個包含高電子濃度之p型線段所構成的氧化鋅奈米線p-n均質接面結構有潛力應用於發展短波長發光元件及光電領域的應用。

Chapter 1
1.1 Taniguchi, N., “On the basic concept of nanotechnology,” Proc. Intl. Conf. Prod, PartⅡ, 1974, 18-23.
1.2 Drexler, K. E., “Engines of creation: The coming era of nanotechnology,” Doubleday, London, 1986.
1.3 Hah, J. H.; Mayya, S.; Hata, M.; Jang, Y. K.; Kim, H. W.; Ryoo, M.; Woo, S. G.; Cho, H. K.; Moon, J. T., “Converging lithography by combination of electrostatic layerby layer self-assembly and 193 nm photolithography: top-down meets botton-up,” J. Vac. Sci. Technol. B. 2006, 24, 2209-2213.
1.4 Alivisatos, P., “Semiconductor clusters, nanocrystals and quantum dots,” Science 1999, 271, 933-934.
1.5 Krans, J. M.; Rutenbeek, J. M. V.; Jongh, L. J. D., “The signature of conductance quantization in metallic point contacts,” Nature 1995, 375, 767-768
1.6 Leobandung, E.; Guo, L.; Wang, Y.; Chou, S. Y., “Observation of quantum effects and coulomb blockade in silicon quantum dot transistors at temperature over 100K,” Appl. Phys. Lett. 1995, 67, 938-940.
1.7 Markovich, G.; Collier, C. P.; Heath, J. R., “Architectonic quantum dot solids,” Acc. Chem. Res. 1999, 32, 415-423.
1.8 Lubick, N.; Betts, K., “Silver socks have cloudy lining,” Environ. Sci. Technol. 2008, 42, 3910-3911.
1.9 Buzea, C.; Pacheco, I. I.; Robbie, K., “Nanomaterials and nanoparticles: sources and toxicity,” Biointerphasese 2007, 2, MR17-MR71.
1.10 Gudiksen, M. S.; Lauhon, L. J.; Wang, J.; Smithn, D. C.; Lieber, C. M., “Growth of nanowires superlattice structures for nanoscale and electronics,” Nature 2002, 415, 617-620.
1.11 Iijima, S., “Helical microtube of graphitic carbon,” Nature 1991, 354, 56-58.
1.12 Tans, S. J.; Verschueren, R. M.; Dekker, C., “Room temperature transistor based on a single carbon nanotube,” Nature 1998, 393, 49-52.
1.13 Yao, Z.; Postma, H. W. C.; Balents, L.; Dekker, C., “Carbon nanotube intramolecular junctions,” Nature 1999, 402, 273-276.
1.14 Derycke, V.; Martel, R.; Appenzaller, J.; Avouis, P., “Carbon nanotube inter and intramolecular logic gates,” Nano Lett. 2001, 1, 453-456.
1.15 Duan, X.; Chi, Y.; Wang, J.; Liber, C. M., “Indium phosphide nanowires as building blocks for nanoscale electronic and optoelectronic devices,” Nature 2001, 409, 66-69.
1.16 Wang, Z. L., “Nanowires and nanobelts materials, properties and devices, metal and semiconductor nanowires, vol. I,” Kluwer Academic Publishers, Dordrecht, Netherlands, 2003.
1.17 Wagner, R. S.; Ellis, W. C., “Vapor-liquid-solid mechanism of single crystal growth,” Appl. Phys. Lett. 1964, 4, 89-90.
1.18 Yang, Y. H.; Wang, C. X.; Wang, B.; Xu, N. S.; Yang, G. W., “ZnO nanowire and amorphous diamond nanocomposites and field emission enhancement,” Chem. Phys. Lett. 2005, 403, 248-251.
1.19 Johnson, M. C.; Lee, C. J.; Bourret-Courchesne, E. D.; Konsek, S. L.; Aloni, S.; Han, W. Q.; Zettl, A., “Growth and morphology of 0.80 eV photoemitting indium nitride nanowires,” Appl. Phys. Lett. 2004, 85, 5670-5672.
1.20 Lee, K. H.; Lee, S. W.; Vanfleet, R. R.; Sigmund, W., “Amorphous silica nanowires grown by the vapor-solid mechanism,” Chem. Phys. Lett. 2003, 376, 498-503.
1.21 Wang, N.; Tang, Y. H.; Zhang, Y. F.; Lee, C. S.; Lee, S. T., “Nucleation and growth of Si nanowires from silicon oxide,” Phys. Rev. B 1998, 58, R16024-R16026.
1.22 Trentler, T. J.; Hickman, K. M.; Goel, S. C.; Viano, A. M.; Gibbons, P. C.; Buhro, W. E., “Solution-liquid-solid growth of crystalline III-V semiconductors: an analogy to vapor-liquid-solid growth,” Science 1995, 270, 1791-1794.
1.23 Z. L. Wang, and J. Song, “Piezoelectric nanogenerators based on zinc oxide nanowire arrays,” Science, 312, 242-246 (2006).
1.24 X. Wang, J. Song, J. Liu, Z. L. Wang, “Direct-current nanogenerator driven by ultrasonic waves,” Science, 316, 102-105 (2007).
1.25 J. H. He, C. L. Hisn, J. Liu, L. J. Chen, and Z. L. Wang, “Piezoelectric gated diode of a single ZnO nanowire,” Adv. Mater. 19, 781-784 (2007).
1.26 M. H. Huang, S. Mao, H. Feick, H. Yan, Y. Wu, H. Kind, E. Weber, R. Russo, and P. Yang, “Room-temperature ultraviolet nanowire nanolasers,” Science, 292, 1897-1899 (2001).
1.27 J. H. Choy, E. S. Jang, J. H. Won, J. H. Chung, D. J. Jang, and Y. W. Kim, “Soft solution route to directionally grown ZnO nanorod arrays on Si wafer; room-temperature ultraviolet laser,” Adv. Mater. 15, 1911-1914 (2003).
1.28 X. Wang, C. Neff, E. Graugnard, Y. Ding, J. S. King, L. A. Pranger, R. Tannenbaum, Z. L. Wang, and C. J. Summers, “Photonic crystals fabricated using patterned nanorod arrays,” Adv. Mater. 17, 2103-2106 (2005).
1.29 Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84, 3654-3656 (2005).
1.30 M. Law, L. E. Greene, J. C. Johnson, R. Saykally, and P. Yang, “Nanowire dye-sensitized solar cells,” Nature Mater. 4, 455-459 (2005).
1.31 Z. L. Wang, “Zinc oxide nanostructures: growth, properties and applications,” J. Phys.: Condens. Matter, 16, R829–R858 (2004).
1.32 X. Y. Kong, and Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts,” Nano Lett. 3, 1625-1631 (2003).
1.33 Z. L. Wang, X. Y. Kong, Y. Ding, P. Gao, W. L. Hughes, R. Yang, and Y. Zhang, “Semiconducting and piezoelectric oxide nanostructures induced by polar surfaces,” Adv. Funct. Mater. 14, 943-956 (2004).
1.34 X. Y. Kong, Y. Ding, R. S. Yang, and Z. L. Wang, “Single-crystal nanorings formed by epitaxial self-coiling of polar nanobelts,” Science, 303, 1348-1351 (2004).
1.35 W. Hughes, and Z. L. Wang, “Formation of piezoelectric single-crystal nanorings and nanobows,” J. Am. Chem. Soc. 126, 6703-6709 (2004).
1.36 P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. Lao, and Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice- structured nanohelices,” Science, 309, 1700-1704 (2005).
1.37 K. Nomura, H. Ohta, K. Ueda, T. Kamiya, M. Hirano, and H. Hosono, “Thin-film transistor fabricated in single-crystalline transparent oxide semiconductor,” Science 300, 1269-1272 (2003).
1.38 S. Y. Lee, E. S. Shim, H. S. Kang, S. S. Pang, and J. S. Kang, “Fabrication of ZnO thin film diode using laser annealing,” Thin Solid Films 437, 31-34 (2005).
1.39 J .H. He, C.L. Hisn, J. Liu, L.J. Chen, and Z.L. Wang, “Piezoelectric gated diode of a single ZnO nanowire,” Adv. Mater. 19, 781-784 (2007).
1.40 M. S. Wagh, L. A. Patil, T. Seth, and D. P. Amalnerkar, “Surface cupricated SnO2-ZnO thick films as a H2S gas sensor,” Mater. Chem. Phys. 84, 228-233 (2004)
1.41 S. J. Pearton, W. H. Heo, M. Ivill, D. P. Norton, and T. Steiner, “Dilute magnetic semiconducting oxides,” Semicond. Sci. Technol. 19, R59-R74 (2004).
1.42 J. Zhou, N. S. Xu and Z. L. Wang, “Dissolving behavior and stability of ZnO wires in biofluids: a study on biodegradability and biocompatibility of ZnO nanostructures,” Adv. Mater. 18, 2432-2435 (2006)
1.43 Z. Fan, and J. G. Lu, “Zinc oxide nanostructures: synthesis and properties,” J. Nanosci Nanotechnol. 5, 1561-1573 (2005).
1.44 X. Wang, Y. Ding, C. J. Summers, and Z. L. Wang, “Large-scale synthesis of six-nanometer-wide ZnO nanobelts,” J. Phys. Chem. B, 108, 8773-8777 (2004).
1.45 L.M. Kukreja, S. Barik, and P. Misra, “Variable band gap ZnO nanostructures grown by pulsed laser deposition,” J. Crystal Growth, 263, 531-535 (2004).
1.46 J. W. Chiou, K. P. Krishna Kumar, J. C. Jan, H. M. Tsai, C. W. Bao, W. F. Pong, F. Z. Chien, M.-H. Tsai, I.-H. Hong, R. Klauser, J. F. Lee, J. J. Wu, and S. C. Liu, “Diameter dependence of the electronic structure of ZnO nanorods determined by X-ray absorption spectroscopy and scanning photoelectron microscopy,” Appl. Phys. Lett. 85, 3220-3222 (2004).
1.47 Z. Fan, and J. G. Lu, “Gate-refreshable nanowire chemical sensors,” Appl. Phys. Lett. 86, 123510-123510-3 (2005).
1.48 B. Tian, X. Zheng, T. J. Kempa, Y. Fang, N. Yu, G. Yu, J. Huang, and C. M. Lieber, “Coaxial silicon nanowires as solar cells and nanoelectronic power sources”, Nature 2007, 449, 885.
1.49 Tian, B.; Kempa, T. J.; Lieber, C. M., “Single nanowire photovoltaics”, Chem. Soc. Rev. 2009, 38, 16.
1.50 Z.L. Wang and J.H. Song, “Piezoelectric nanogenerators based on zinc oxide nanowire arrays”, Science 2006, 312, 242.
1.51 X. D. Wang, J. H. Song, J. Liu, Z. L. Wang, “Direct-Current Nanogenerator Driven by Ultrasonic Waves” Science 2007, 316, 102.
1.52 Y. Qin, X. D. Wang, Z. L. Wang, “Microfibre–nanowire hybrid structure for energy scavenging” Nature 2008, 451, 809.
1.53 T. J. Kempa, B. Tian, D. R. Kim, J. Hu, X. Zheng, C. M. Lieber, “Single and tandem axial p-i-n nanowire photovoltaic devices” Nano Lett. 2008, 8, 3456.
1.54 S. Xu, Y. Wei, J. Liu, R. Yang, Z. L. Wang, “Integrated Multilayer Nanogenerator Fabricated Using Paired Nanotip-to-Nanowire Brushes” Nano Lett. 2008, 8, 4027.
1.55 Z. L. Wang, “Towards Self-Powered Nanosystems: From Nanogenerators to Nanopiezotronics” Adv. Func. Mater. 2008, 18, 3553.
1.56 Z. L. Wang, “Self Powered Nanotech” Sci. Am. 2008, 298, 82.
1.57 C. H. Park, S. B. Zhang, S. H. Wei, “Origin of p-type doping difficulty in ZnO: The impurity perspective” Phys. Rev. B 2002, 66, 073202.
1.58 W. J. Lee, J. Kang, K. J. Chang, “Defect properties and p-type doping efficiency in phosphorus-doped ZnO” Phys. Rev. B 2006, 73, 024117.
1.59 B. Xiang, P. Wang, X. Zhang, S. A. Dayeh, D. P. R. Aplin, C. Soci, D. Yu, D. Wang, “Rational synthesis of p-type zinc oxide nanowire arrays using simple chemical vapor deposition” Nano Lett. 2007, 7, 323.
1.60 G. D. Yuan, W. J. Zhang, J. S. Jie, X. Fan, J. A. Zapien, Y. H. Leung, L. B. Luo, P. F. Wang, C. S. Lee, S. T. Lee, “ p-Type ZnO Nanowire Arrays” Nano Lett. 2008, 8, 2591.
1.61 A. Sandhu, “The future of ultraviolet LEDs” Nat. Photonics 2007, 1, 38.
1.62 M. H. Huang, S. Mao, H. Feick, H. Yan, Y. Wu, Hannes Kind, E. Weber, R. Russo, P. Yang, “Room-Temperature Ultraviolet Nanowire Nanolasers” Science 2001, 292, 1897.
1.63 A. Kinoshita, H. Hirayama, M. Ainoya, Y. Aoyagi, A. Hirata, “Room-temperature operation at 333 nm of Al0.03Ga0.97N/Al0.25Ga0.75N quantum-well light-emitting diodes with Mg-doped superlattice layers” Appl. Phys. Lett. 2000, 77, 175.
1.64 S. Koizumi, K. Watanabe, M. Hasegawa, H. Kanda, “Ultraviolet Emission from a Diamond pn Junction” Science 2001, 292, 1899.
1.65 K. Watanabe, T. Taniguchi, H. Kanda, “Direct-bandgap properties and evidence for ultraviolet lasing of hexagonal boron nitride single crystal” Nat. Mater. 2004, 3, 404.
1.66 J. H. Lim, C. K. Kang, K. K. Kim, I. K. Park, D. K. Hwang, S. J. Park, “UV electroluminescence emission from ZnO light-emitting diodes grown by high-temperature radiofrequency sputtering” Adv. Mater. 2006, 18, 2720.
1.67 Z. Zhong, F. Qian, D. Wang, C. M. Lieber, “Synthesis of p-Type gallium nitride nanowires for electronic and photonic nanodevices” Nano Lett. 2003, 3, 343.
1.68 S. K. Lee, T. H. Kim, S. Y. Lee, K. C. Choi, P. Yang, “High brightness gallium nitride nanowire UV-blue LEDs” Philos. Mag. 2007, 87, 2105.
1.69 X. M. Zhang, M. Y. Lu, Y. Zhang, L. J. Chen, Z. L. Wang, “Fabrication of a high-brightness blue-light-emitting diode using a ZnO-nanowire array grown on p-GaN thin film” Adv. Mater. 2009, 21, 2767–2770.
1.70 J. C. Sun, J. Z. Zhao, H. W. Liang, J. M. Bian, L. Z. Hu, H. Q. Zhang, X. P. Liang, W. F. Liu, G. T. Du, “Realization of ultraviolet electroluminescence from ZnO homojunction with n-ZnO/p-ZnO:As/GaAs structure” Appl. Phys. Lett. 2007, 90, 121128.
1.71 S. Chu, J. H. Lim, L. J. Mandalapu, Z. Yang, L. Li, J. L. Liu,“Sb-doped p-ZnO/Ga-doped n-ZnO homojunction ultraviolet light emitting diodes” Appl. Phys. Lett. 2008, 92, 152103.
1.72 C. H. Park, S. B. Zhang, S. H. Wei, “Origin of p-type doping difficulty in ZnO: The impurity perspective” Phys. Rev. B 2002, 66, 073202.
1.73 W. J. Lee, J. Kang, K. J. Chang, “Defect properties and p-type doping efficiency in phosphorus-doped ZnO” Phys. Rev. B 2006, 73, 024117
1.74 Y. Yang, X. W. Sun, B. K. Tay, G. F. You, S. T. Tan, K. L. Teo, “A p-n homojunction ZnO nanorod light-emitting diode formed by As ion implantation” Appl. Phys. Lett. 2008, 93, 253107.
1.75 J. Y. Zhang, P. J. Li, H. Sun, X. Shen, T. S. Deng, K. T. Zhu, Q. F. Zhang, J. L. Wu, “Ultraviolet electroluminescence from controlled arsenic-doped ZnO nanowire homojunctions” Appl. Phys. Lett. 2008, 93, 021116.
1.76 X. W. Sun, B. Ling, J. L. Zhao, S. T. Tan, Y. Yang, Y. Q. Shen, Z. L. Dong, X. C. Li, “Ultraviolet emission from a ZnO rod homojunction light-emitting diode” Appl. Phys. Lett. 2009, 95, 133124.
1.77 Y. Zhang, N. Wang, S. Gao, R. He, S. Miao, J. Liu, J. Zhu and X. Zhang, “A simple method to synthesize nanowires.” Chem. Mater. 14, 3564-3568 (2002).
1.78 Y. C. Kong, D. P. Yu, B. Zhang, W. Fang and S. Q. Feng, “Ultraviolet-emitting ZnO nanowires synthesized by a physical vapor deposition approach,” Appl. Phys. Lett. 78, 407- 409 (2001).
1.79 Z. Zhu, “Self-organized growth of II-VI wide bandgap quantum dot structures,” Phys. Status Solidi b 202, 827(1997).
1.80 W. I. Park, S. J. An, G. C. Yi and H. M. Jang, “Metalorganic vapor phase epitaxial growth of high-quality ZnO films on Al2O3 (001),” J. Mater. Res. 16, 1358(2001).
1.81 W. I. Park, D. H. Kim, S. W. Jung and G. C. Yi, “Metalorganic vapor-phase epitaxial growth of vertically well-aligned ZnO nanorods,” Appl. Phys. Lett. 80, 4232-4234 (2002).
1.82 W. I. Park, G. C. Yi, M. Y. Kim and S. J. Pennycook, "ZnO nanoneedles grown vertically on Si substrates by non-catalytic vapor-phase epitaxy,” Adv. Mater. 14, 1841-1843(2002).
1.83 L. E. Greene, M. Law, J. Goldberger, F. Kim, J. C. Johnson, Y. F. Zhang, R. J. Saykally, and P. D. Yang, “Low-temperature wafer-scale production of ZnO nanowire arrays,” Angew. Chem. Int. Ed. 42, 3031-3034 (2003).
1.84 L. Vayssieres, “On the design of advanced metal oxide nanomaterials,” Inter. J. Nanotechnology, 1, 1-41 (2004).
1.85 L. E. Greene, M. Law, Da. H. Tan, M. Montano, J. Goldberger, G. Somorjai, and P. Yang, “General route to vertical ZnO nanowire arrays using textured ZnO seeds,” Nano Lett. 5, 1321-1326 (2005).
1.86 H. Rensmo, K. Keis, H. Lindström, S. Södergren, A. Solbrand, A. Hagfeldt, S. E. Lindquist, L. N. Wang, and M. Muhammed, “High light-to-energy conversion efficiencies for solar cells based on nanostructured ZnO electrodes,” J. Phys. Chem. B 101, 2598 (1997).
1.87 M. Law, L. E. Greene, J. C. Johnson, R. Saykally, and P. D. Yang, “Nanowire dye-sensitized solar cells,” Nat. Mater. 4, 455- (2005).
1.88 M. H. Huang, S. Mao, H. Feick, H. Yan, Y. Wu, H. Kind, E. Weber, R. Russo, and P. Yang, “Room-temperature ultraviolet nanowire nanolasers,” Science 292, 1897-1900 (2001).
1.89 Z. Fan, and J. G. Lu, “Zinc oxide nanostructures: synthesis and properties,” J. Nanosci Nanotechnol. 5, 1561-1573 (2005).
1.90 D. Zhao, Y. Liu, D. Shen, Y. Lu, J. Zhang, and X. Fan, “Photoluminescence properties of MgxZn1–xO alloy thin films fabricated by the sol-gel deposition method,” J. Appl. Phys., 90, 5561-5563 (2001).
1.91 C. H. Park, S. B. Zhang, and S. H. Wei, “Origin of p-type doping difficulty in ZnO: the impurity perspective,” Phys. Rev. B, 66, 073202-073202-3 (2002).
1.92 D. A. Schwartz, K. R. Kittilstved, and D. R. Gamelin, “Above-room-temperature ferromagnetic Ni2+-doped ZnO thin films prepared from colloidal diluted magnetic semiconductor quantum dots,” Appl. Phys. Lett. 85, 1395-1397 (2004).
1.93 C. Klingshirn, “ZnO: materials, physics and applications,” Chem. Phys. Chem., 8, 782-803 (2007).
1.94 U. Philipose and S. V. Nair, S. Trudel, C. F. de Souza and S. Aouba, R. H. Hill, H. E. Ruda, “High-temperature ferromagnetism in Mn-doped ZnO nanowires,” Appl. Phys. Lett. 88, 263101-263101-3 (2006).
1.95 H. S. Kang, B. D. Ahn, J. H. Kim, G. H. Kim, S. H. Lim, H. W. Chang, and S. Y. Lee, “Structural, electrical, and optical properties of p-type ZnO thin films with Ag dopant,” Appl. Phys. Lett. 88, 202108-202108-3 (2006).
1.96 C. L. Hsu, S. J. Chang, Y. R. Lin, S. Y. Tsai and I. C. Chen, “Vertically well aligned p-doped ZnO nanowires synthesized on ZnO–Ga/glass templates,” Chem. Commun. 3571-3573 (2005).
1.97 B. Xiang, P. Wang, X. Zhang, S. A. Dayeh, D. P. R. Aplin, C. Soci, D. Yu, and D. Wang, “Rational synthesis of p-type zinc oxide nanowire arrays using simple chemical vapor deposition,” Nano Lett. 7, 323-328 (2007).
1.98 Y. C. Choi, W. S. Kim, Y. S. Park, S. M. Lee, D. J. Bae, H. Y. Lee, G. S. Park, W. B. Choi. N. S. Lee and J. M. Kim, “Catalytic growth of beta-Ga2O3 nanowires by arc discharge,” Adv. Mater., 12, 746 (2000).
1.99 M. H. Huang, Y. Y. Wu, H. Ferick, N. Tran, E. Weber and P. D. Yang, “Catalytic growth of zinc oxide nanowires by vapor transport”, Adv. Mater., 13, 113 (2001).
1.100 L.E. Greene, M. Law, J. Goldberger, F. Kim, J. C. Johnson, Y. Zhang, R. J. Saykally and P. D. Yang, “Low-temperature wafer-scale production of ZnO nanowire arrays”, Angew. Chem. Int. Ed., 42, 3031 (2003).
1.101 J. Q. Hu, Q. Li, N. B. Wong, C. S. Lee and S. T. Lee, “Synthesis of uniform hexagonal prismatic ZnO whiskers”, Chem. Mater., 14, 1216 (2002).
1.102 B. D. Yao, Y. F. Chan and N. Wang, “Formation of ZnO nanostructures by a simple way of thermal evaporation”, Appl. Phys. Lett., 81, 757 (2002).
1.103 C. Y. Geng, Y. iang, Y. Yao, X. M. Meng, J. A. Zapien, C. S. Lee. Y. Lifshitz and S. T. Lee, “Well-aligned ZnO nanowire arrays fabricated on silicon substrates”, Adv. Funct. Mater. 14, 589 (2004).
1.104 M. Andres Verges, A. Mifsud and C. J. Serna, “Formation of rod-like zinc oxide microcrystals in homogeneous solutions”, J. Chem. Soc., Faraday Trans., 86, 959 (1990).
1.105 L. Schmidt-Mende and J. L. MacManus-Driscoll, “ZnO-nanostructures, defects, and devices’’ Mater. Today, 10, 40 (2007).
1.106 Y. Sato and S. Sato, “Preparation and some properties of nitrogen-mixed ZnO thin films”, Thin Solid Films, 282, 445 (1996).
1.107 X. L. Guo, H. Tabata and T. Kawai, “Pulsed laser reactive deposition of p-type ZnO film enhanced by an electron cyclotron resonance source”, J. Cryst. Growth, 223, 135 (2001).
1.108 K. Nakahara, H. Takasu, P. Fons, A. Yamada, K. Iwata, K. Matsubara, R. Hunger and S. Niki, “Interactions between gallium and nitrogen dopants in ZnO films grown by radical-source molecular-beam epitaxy”, Appl. Phys. Lett., 79, 4139 (2001).
1.109 D. C. Look, D. C. Reynolds, C. W. Litton, R. L. Jones, D. B. Eason and G. Cantwell, “Characterization of homoepitaxial p-type ZnO grown by molecular beam epitaxy”, Appl. Phys. Lett., 81, 1830 (2002).
1.110 J. M. Bian, X. M. Li., C. Y. Zhang, W. D. Yu and X. D. Gao, “p-type ZnO films by monodoping of nitrogen and ZnO-based p-n homojunctions”, Appl. Phys. Lett., 85, 4070 (2004).
1.111 A. Kobayashi, O. F. Sankey and J. D. Dow, “Deep energy-level of defects in the wurtzite semiconductors AlN, CdS, CdSe, ZnS and ZnO”, Phys. Prv. B, 28, 946 (1983).
1.112 C. H. Park, S. B. Zhang and S. H. Wei, “Origin of p-type doping difficulty in ZnO: the impurity perspective”, Phys. Rev. B 66, 073202 (2002).
1.113 E. C. Lee, Y. S. Kim, Y. G. Jin and K. J. Chang, “Compensation mechanism for N acceptors in ZnO”, Phys. Rev. B, 64, 085120 (2001).
1.114 W. J. Lee, J. Kang and K. J. Chang, “Defect properties and p-type doping efficiency in phosphorus-doped ZnO”, Phys. Rev. B, Condens. Matter, 73, 024117 (2007).
1.115 S. Limpijumnong, S. B. Zhang, S. H. Wei and C. H. Park, “Dpoing by large-size-mismatched impurities: the microscopic origin of arsenic- or antimony-doped p-type zinc oxide”, Phys. Rev. Lett., 92, 155504 (2004).
1.116 H. S. Kang, B. D. Ahn, J. H. Kim, G. H. Kim, S. H. Lim, H. W. Chang, and S. Y. Lee, “Structural, electrical, and optical properties of p-type ZnO thin films with Ag dopant,” Appl. Phys. Lett. 88, 202108-202108-3 (2006).
1.117 J. B. Cui and U. J. Gibson, “Electrodeposition and room temperature ferromagnetic anisotropy of Co and Ni-doped ZnO nanowire arrays,” Appl. Phys. Lett. 87, 133108-133108-3 (2005).
1.118 B. D. Yuhas, D. O. Zitoun, P. J. Pauzauskie, R. He, P. Yang, “Transition-metal doped zinc oxide nanowires,” Angew. Chem. Int. Ed. 45, 420-423 (2006).
1.119 C. Qian, F. Kim, L. Ma, F. Tsui, P. Yang, and J. Liu, “Solution-phase synthesis of single-crystalline iron phosphide nanorods/nanowires,” J. Am. Chem. Soc. 126, 1195-1198 (2004).
1.120 Y. Li, M. A. Malik, and P. O’Brien, “Synthesis of single-crystalline CoP nanowires by a one-pot metal-organic route,” J. Am. Chem. Soc. 127, 16020-16021 (2005).

Chapter 2
2.1 Dong, L.; Bush, J.; Chirayos, V.; Solanki, R.; Jiao, J.; Ono, Y.; Conley, J. F.; Ulrich, B. D., “Dielectrophoretically controlled fabrication of single crystal nickel silicide nanowire interconnects,” Nano Lett. 2005, 5, 2112-2115.
2.2 Z. W. Pan, Z. R. Dai, Z. L. Wang, “Nanobelts of semiconducting oxides” Science 2001, 291, 1947.
2.3 Z. R. Dai, Z. W. Pan, Z. L. Wang, “Novel Nanostructures of Functional Oxides Synthesized by Thermal Evaporation” Adv. Funct. Mater. 2003, 13, 9.

Chapter 3
3.1 Z. L. Wang, and J. Song, “Piezoelectric nanogenerators based on zinc oxide nanowire arrays,” Science, 312, 242-246 (2006).
3.2 X. Wang, J. Song, J. Liu, Z. L. Wang, “Direct-current nanogenerator driven by ultrasonic waves,” Science, 316, 102-105 (2007).
3.3 J. H. He, C. L. Hisn, J. Liu, L. J. Chen, and Z. L. Wang, “Piezoelectric gated diode of a single ZnO nanowire,” Adv. Mater. 19, 781-784 (2007).
3.4 M. H. Huang, S. Mao, H. Feick, H. Yan, Y. Wu, H. Kind, E. Weber, R. Russo, and P. Yang, “Room-temperature ultraviolet nanowire nanolasers,” Science, 292, 1897-1899 (2001).
3.5 J. H. Choy, E. S. Jang, J. H. Won, J. H. Chung, D. J. Jang, and Y. W. Kim, “Soft solution route to directionally grown ZnO nanorod arrays on Si wafer; room-temperature ultraviolet laser,” Adv. Mater. 15, 1911-1914 (2003).
3.6 X. Wang, C. Neff, E. Graugnard, Y. Ding, J. S. King, L. A. Pranger, R. Tannenbaum, Z. L. Wang, and C. J. Summers, “Photonic crystals fabricated using patterned nanorod arrays,” Adv. Mater. 17, 2103-2106 (2005).
3.7 Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84, 3654-3656 (2005).
3.8 M. Law, L. E. Greene, J. C. Johnson, R. Saykally, and P. Yang, “Nanowire dye-sensitized solar cells,” Nature Mater. 4, 455-459 (2005).
3.9 Z. L. Wang, “Zinc oxide nanostructures: growth, properties and applications,” J. Phys.: Condens. Matter, 16, R829–R858 (2004).
3.10 X. Y. Kong, and Z. L. Wang, “Spontaneous polarization-induced nanohelixes, nanosprings, and nanorings of piezoelectric nanobelts” Nano Lett. 3, 1625-1631 (2003).
3.11 Z. L. Wang, X. Y. Kong, Y. Ding, P. Gao, W. L. Hughes, R. Yang, and Y. Zhang, “Semiconducting and piezoelectric oxide nanostructures induced by polar surfaces,” Adv. Funct. Mater. 14, 943-956 (2004).
3.12 X. Y. Kong, Y. Ding, R. S. Yang, and Z. L. Wang, “Single-crystal nanorings formed by epitaxial self-coiling of polar nanobelts” Science, 303, 1348-1351 (2004).
3.13 W. Hughes, and Z. L. Wang, “Formation of piezoelectric single-crystal nanorings and nanobows” J. Am. Chem. Soc. 126, 6703-6709 (2004).
3.14 P. X. Gao, Y. Ding, W. Mai, W. L. Hughes, C. Lao, and Z. L. Wang, “Conversion of zinc oxide nanobelts into superlattice- structured nanohelices” Science, 309, 1700-1704 (2005).
3.15 Z. Fan, and J. G. Lu, “Zinc oxide nanostructures: synthesis and properties” J. Nanosci Nanotechnol. 5, 1561-1573 (2005).
3.16 C. H. Park, S. B. Zhang, and S. H. Wei, “Origin of p-type doping difficulty in ZnO: the impurity perspective” Phys. Rev. B, 66, 073202-073202-3 (2002).
3.17 H. S. Kang, B. D. Ahn, J. H. Kim, G. H. Kim, S. H. Lim, H. W. Chang, and S. Y. Lee, “Structural, electrical, and optical properties of p-type ZnO thin films with Ag dopant” Appl. Phys. Lett. 88, 202108-202108-3 (2006).
3.18 C. L. Hsu, S. J. Chang, Y. R. Lin, S. Y. Tsai and I. C. Chen, “Vertically well aligned p-doped ZnO nanowires synthesized on ZnO–Ga/glass templates” Chem. Commun. 3571-3573 (2005).
3.19 B. Xiang, P. Wang, X. Zhang, S. A. Dayeh, D. P. R. Aplin, C. Soci, D. Yu, and D. Wang, “Rational synthesis of p-type zinc oxide nanowire arrays using simple chemical vapor deposition” Nano Lett. 7, 323-328 (2007).
3.20 W. J. Lee, J. Kang, K. J. Chang, “Defect properties and p-type doping efficiency in phosphorus-doped ZnO” Phys. Rev. B 2006, 73, 024117.

Chapter 4
4.1 B. Xiang, P. Wang, X. Zhang, S. A. Dayeh, D. P. R. Aplin, C. Soci, D. Yu, D. Wang, “Rational synthesis of p-type zinc oxide nanowire arrays using simple chemical vapor deposition” Nano Lett. 2007, 7, 323.
4.2 G. D. Yuan, W. J. Zhang, J. S. Jie, X. Fan, J. A. Zapien, Y. H. Leung, L. B. Luo, P. F. Wang, C. S. Lee, S. T. Lee, “Vertically aligned p-type single-crystalline GaN nanorod arrays on n-Type Si for heterojunction photovoltaic cells” Nano Lett. 2008, 8, 2591.
4.3 B. Tian, X. Zheng, T. J. Kempa, Y. Fang, N. Yu, G. Yu, J. Huang, C. M. Lieber, “Coaxial silicon nanowires as solar cells and nanoelectronic power sources” Nature 2007, 449, 885.
4.4 Z. L. Wang, J. H. Song, “Piezoelectric nanogenerators based on zinc oxide nanowire arrays” Science 2006, 312, 242.
4.5 Y. F. Gao, Z. L. Wang, “Electrostatic potential in a bent piezoelectric nanowire. The fundamental theory of nanogenerator and nanopiezotronics” Nano Lett. 2007, 7, 2499.
4.6 R.S. Yang, Y. Qin, L.M. Dai, Z. L. Wang, “Power generation with laterally packaged piezoelectric fine wires” Nature Nanotech. 2008, 4, 34.

Chapter 5
5.1 B. Xiang, P. Wang, X. Zhang, S. A. Dayeh, D. P. R. Aplin, C. Soci, D. Yu, D. Wang, “Rational synthesis of p-type zinc oxide nanowire arrays using simple chemical vapor deposition” Nano Lett. 2007, 7, 323.
5.2 M. P. Lu, J. Song, M. Y. Lu, M. T. Chen, Y. Gao, L. J. Chen, Z. L. Wang, “Piezoelectric nanogenerator using p-type ZnO nanowire arrays” NanoLett. 2009, 9, 1223.
5.3 Z. L. Wang, J. H. Song, “Piezoelectric nanogenerators based on zinc oxide nanowire arrays” Science 2006, 312, 242.
5.4 Lin, S. S.; Hong, J. I.; Song, J. H.; Zhu, Y.; He, H. P.; Xu, Z.; Wei, Y. G.; Ding, Y.; Snyder, R. L.; Wang, Z. L. “Phosphorus doped Zn1-xMgxO nanowire arrays” Nano. Lett. 2009, 9, 3877.
5.5 S. S. Lin, J. H. Song, Y. F. Lu, Z. L. Wang, “Identifying individual n- and p-type ZnO nanowires by the output voltage sign of piezoelectric nanogenerator” Nanotechnology 2009, 20, 365703.
5.6 W. K. Hong, J. I. Sohn, S. S. Hwang, G. Jo, S. Song, S. M. Kim, H. J. Ko, S. J. Park, M. E. Welland, T. Lee, “Tunable electronic transport characteristics of surface-architecture-controlled ZnO nanowire field effect transistors” Nano Lett. 2008, 8, 950.
5.7 K. Vanheusden, C. H. Seager, W. L. Warren, D. R. Tallant, J. A. Voigt, “Correlation between photoluminescence and oxygen vacancies in ZnO phosphors” Appl. Phys. Lett. 1996, 68, 403.
5.8 N. Pan, X. Wang, M. Li, F. Li, J. G. Hou, “Strong surface effect on cathodoluminescence of an individual tapered ZnO nanorod” J. Phys. Chem. C 2007, 111, 17265.
5.9 H. Xue, N. Pan, R. Zeng, M. Li, X. Sun, Z. Ding, X. Wang, J. G. Hou, “Probing the surface effect on deep-level emissions of an individual ZnO nanowire via spatially resolved cathodoluminescence” J. Phys. Chem. C 2009, 113, 12715.
5.10 Y. C. Chang, L. J. Chen, “ZnO Nanoneedles with Enhanced and Sharp Ultraviolet Cathodoluminescence Peak” J. Phys. Chem. C 2007, 111, 1268.
5.11 M. Yin, Y. Gu, I. L. Kuskovsky, T. Andelman, Y. Zhu, G. F. Neumark, S. O’Brien, “Zinc Oxide Quantum Rods” J. Am. Chem. Soc. 2004, 126, 6206.
5.12 A N Baranov, G N Panin, T. W. Kang, Y. J. Oh, “Growth of ZnO nanorods from a salt mixture” Nanotechnology 2005, 16, 1918.
5.13 V. A. Fonoberov, A. A. Balandin, “Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect” Phys. Rev. B 2004, 70, 195410.
5.14 M. Combescot, R. Combescot, B. Roulet, “The exciton dead layer revisited” Eur. Phys. J. B 2001, 23, 139.
5.15 K. Sakai, T. Kakeno, T. Ikari, S. Shirakata, T. Sakemi, K. Awai, T. Yamamoto, “Defect centers and optical absorption edge of degenerated semiconductor ZnO thin films grown by a reactive plasma deposition by means of piezoelectric photothermal spectroscopy” J. Appl. Phys. 2006, 99, 043508.
5.16 B. E. Sernelius, K. F. Berggren, Z. C. Jin, I. Hamberg, C. G. Granqvist, “Band-gap tailoring of ZnO by means of heavy Al doping” Phys. Rev. B 1988, 37, 10244.
5.17 R. Martel, T. Schmidt, H. R. Shea, T. Hertel, Ph. Avouris, “Single- and multi-wall carbon nanotube field-effect transistors” Appl. Phys. Lett. 1998, 73, 2447.
5.18 Z. Fan, D. Wang, P. H. Chang, W. Y. Tseng, J. G. Lu, “ZnO nanowire field-effect transistor and oxygen sensing property” Appl. Phys. Lett. 2004. 85, 5923.
5.19 W. K. Hong, J. I. Sohn, S. S. Hwang, G. Jo, S. Song, S. M. Kim, H. J. Ko, S. J. Park, M. E. Welland, T. Lee, “Tunable electronic transport characteristics of surface-architecture-controlled ZnO nanowire field effect transistors” Nano Lett. 2008, 8, 950–956.
5.20 K. I. Hagemark, “Defect structure of Zn-doped ZnO” J. Solid State Chem. 1976, 16, 293.
5.21 D. C. Reynolds, D. C. Look, B. Jogai, “Fine structure on the green band in ZnO” J. Appl. Phys. 2001, 89, 6189.
5.22 W. Shan, W. Walukiewicz, J. W. Ager III, K. M. Yu, H. B. Yuan, H. P. Xin, G. Cantwell, J. J. Song, “Nature of room-temperature photoluminescence in ZnO” Appl. Phys. Lett. 2005, 86, 191911.
5.23 M. K. Patra, K. Manzoor, M. Manoth, S. R. Vadera, N. Kumar, “Studies of luminescence properties of ZnO and ZnO:Zn nanorods prepared by solution growth technique ”J. Lumin. 2008, 128, 267.
5.24 M. A. Zimmler, T. Voss, C. Ronning, F. Capasso, “Exciton-related electroluminescence from ZnO nanowire light-emitting diodes” Appl. Phys. Lett. 2009, 94, 241120.

Chapter 7
7.1 S. Xu, C. S. Lao, B. Weintraub, Z. L. Wang, “Density-controlled growth of aligned ZnO nanowire arrays by seedless chemical approach on smooth surfaces” J. Mater. Res. 2008, 23, 2072.
7.2 X. Wang, J. Song, P. Li, J. H. Ryou, R. D. Dupuis, C. J. Summers, Z. L. Wang, “Growth of uniformly aligned ZnO nanowire heterojunction arrays on GaN, AlN, and Al0.5Ga0.5N substrates” J. Am. Chem. Soc. 2005, 127, 7920.
7.3 Y. Qin, X. D. Wang, Z. L. Wang, “Microfibre–nanowire hybrid structure for energy scavenging"” Nature 2008, 451, 809.
7.4 W. I. Park and G.-C. Yi, “Electroluminescence in n-ZnO nanorod arrays vertically grown on p-GaN,” Adv. Mater. 16, 87-90 (2004).
7.5 C. Yuen, S. F. Yu, S. P. Lau, and T. P. Chen, “Fabrication of n-ZnO:Al/p-SiC(4H) heterojunction light-emitting diodes by filtered cathodic vacuum arc technique,” Appl. Phys. Lett. 86, 241111 (2005).
7.6 Ya. I. Alivov, J. E. Van Nostrand, D. C. Look, M. V. Chukichev, and B. M. Ataev, “Fabrication and characterization of n-ZnO/p-AlGaN heterojunction light-emitting diodes on 6H-SiC substrates” Appl. Phys. Lett. 83, 2943-2945 (2003).
7.7 J. Black, H. Lowckwood, S. Mayburg, “Recombination Radiation in GaAs” J. Appl. Phys. 1963, 34, 178.
7.8 M. G. Craford, “Flip-chip bonding optimizes opto-ICs” IEEE Circuits Devices 1992, 8, 25.
7.9 Y. Naoi, K. Ikeda, T. Hama, K. Ono, R. Choi, T. Fukumoto, K. Nishino, S. Sakai, S. M. Lee, M. Koike, “Blue light emitting diode fabricated on a-plane GaN film over r-sapphire substrate and on a-plane bulk GaN substrate” Phys. Status Solidi C 2007, 4, 2810.
7.10 Z. Zhong, F. Qian, D. Wang, C. M. Lieber, “Synthesis of p-Type gallium nitride nanowires for electronic and photonic nanodevices” Nano Lett. 2003, 3, 343.
7.11 F. A. Ponce, D. P. Bour, “Nitride-based semiconductors for blue and green light-emitting devices” Nature 1997, 386, 351.
7.12 T. Kobayashi, S. Egawa, M. Sawada, T. Honda, “GaN-based dchottky-type UV light-emitting diodes and their integration for flat-panel displays” Phys. Status Solidi C 2007, 4, 61.
7.13 J. D. Ye, S. L. Gu, S. M. Zhu, W. Liu, S. M. Liu, R. Zhang, Y. Shi, and Y. D. Zheng, “Electroluminescent and transport mechanisms of n-ZnO/p-Si heterojunctions,” Appl. Phys. Lett. 88, 182112 (2006).
7.14 Lu, M. P.; Song, J.; Lu, M. Y.; Chen, M. T.; Gao, Y.; Chen, L. J., “Piezoelectric nanogenerator using p-type ZnO nanowire arrays,” Nano Lett. 2009, 9, 1223-1227.
7.15 Wang, Z. L., “Towards self-powered nanosystems,” Adv. Funct. Mater. 2008, 18, 3553-3567.
7.16 Wang, Z. L., “Self power nanotech,” Sci. Am. 2008, 298, 82-87.
7.17 Wang, Z. L.; Song, J. H., “Piezoelectric nanogenerators based on zinc oxide nanowire arrays,” Science 2006, 312, 242-246.
7.18 Wang, X. D.; Song, J. H.; Liu, J.; Wang. Z. L., “Direct current nanogenerator driven by ultrasonic waves,” Science 2007, 316, 102-106.
7.19 Qin, Y.; Wang, X. D.; Wang, Z. L., “Microfiber nanowire hybrid structure for energy scavenging,” Nature 2008, 451, 809-813.
7.20 Xu, S.; Wei, Y.; Liu, J.; Yang, R.; Wang, Z. L., “Integrated multilayer nanogenerator fabricated using paired nanotip to nanowire brushes,” Nano Lett. 2008, 8, 4027-4032.
7.21 A. B. Djurisić and Y. H. Leung, “Optical properties of ZnO nanostructures,” Small 2, 944-961 (2006).