Growth of catalyst-free high-quality ZnO nanowires by thermal evaporation under air ambient
© Liu et al; licensee Springer. 2012
Received: 22 March 2012
Accepted: 13 April 2012
Published: 13 April 2012
ZnO nanowires have been successfully fabricated on Si substrate by simple thermal evaporation of Zn powder under air ambient without any catalyst. Morphology and structure analyses indicated that ZnO nanowires had high purity and perfect crystallinity. The diameter of ZnO nanowires was 40 to 100 nm, and the length was about several tens of micrometers. The prepared ZnO nanowires exhibited a hexagonal wurtzite crystal structure. The growth of the ZnO nanostructure was explained by the vapor-solid mechanism. The simplicity, low cost and fewer necessary apparatuses of the process would suit the high-throughput fabrication of ZnO nanowires. The ZnO nanowires fabricated on Si substrate are compatible with state-of-the-art semiconductor industry. They are expected to have potential applications in functional nanodevices.
Keywordszinc oxide nanowire thermal evaporation
In the past decade, significant interest has emerged in the synthesis of one-dimensional semiconductor materials, such as Si [1–3], SiC [4, 5], GaN [6–8], SnO2  and ZnO [10–13]. Among these nanoscale semiconductors, ZnO has attracted a great deal of attention because of its potential as a large direct band gap semiconductor (Eg is about 3.35 eV at room temperature) with high exciton binding energy (60 meV). It can act as building blocks for nano-FET, nanolasers, photodetectors and gas sensors [8, 14]. In addition, ZnO nanowires have excellent field emission for its good hardness, thermal stability and resistance to oxidation [15, 16].
Recently, many methods have been developed to synthesize ZnO nanowires, for example, carbon thermal reduction [13, 17], chemical vapor deposition [12, 18], physical vapor deposition , electrodeposition , aqueous synthesis  and solvothermal technique . In this paper, we synthesized ZnO nanowires by thermal evaporation without a catalyst under air ambient. The reactions were carried out in a traditional horizontal furnace with one end open at 750°C. The gray-white product was successfully deposited on the Si substrate. The process does not need any metal catalyst, so it avoids catalyst contamination. Furthermore, the simplicity, low cost and fewer necessary apparatuses of the process would suit the high-throughput fabrication of ZnO nanowires.
The as-synthesized products were characterized by X-ray diffraction (XRD) with CuKα radiation (wavelength, λ = 1.5406 Å), field emission scanning electron microscopy (SEM) (Hitachi S-4800, Hitachi Ltd., Tokyo, Japan), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM) (JEOL JEM2010F, JEOL Co., Ltd., Beijing, China).
Results and discussion
ZnO nanowires with high purity and perfect crystallinity were fabricated by simple thermal evaporation of pure Zn powders under air ambient without any catalyst. The diameter of the ZnO nanowires was 40 to 100 nm, and the length was about several tens of micrometers. Some aligned ZnO nanowires with smooth surface were also detected. The growth of ZnO nanostructure was explained by the V-S mechanism. The prepared ZnO nanowires exhibited a hexagonal wurtzite crystal structure. The as-fabricated ZnO nanowires are expected to find applications in nanosensors and nanodetectors.
Dr. Ping Liu got her PhD degree in 2010. She has devoted her effort in the research of one-dimensional semiconductor materials for 7 years. Her research interest lies in the fabrication and application of zinc oxide nanowires. She has published her work in several important international journals.
The authors thank the Foundation of He'nan Educational Committee (no. 2011A470015) and the Henan province science and technology tackling key project (no. 102102210444).
- Shiu SC, Lin SB, Hung SC, Lin CF: Influence of pre-surface treatment on the morphology of silicon nanowires fabricated by metal-assisted etching. Appl Surf Sci 2011, 257: 1829–1834. 10.1016/j.apsusc.2010.08.086View Article
- Cheng YK, Chie G, Bau TD: Photovoltaic characteristics of silicon nanowire arrays synthesized by vapor-liquid-solid process. Sol Energ Mat Sol C 2011, 95: 154–157. 10.1016/j.solmat.2010.04.028View Article
- Kumar D, Srivastava SK, Singh PK, Husain M, Kumar V: Fabrication of silicon nanowire arrays based solar cell with improved performance. Sol Energ Mat Sol C 2011, 95: 215–218. 10.1016/j.solmat.2010.04.024View Article
- Zhou WM, Yang B, Yang ZX, Zhu F, Yan LJ, Zhang YF: Large-scale synthesis and characterization of SiC nanowires by high-frequency induction heating. Appl Surf Sci 2006, 252: 5143–5148. 10.1016/j.apsusc.2005.07.031View Article
- Li XT, Chen XH, Song HH: Preparation of silicon carbide nanowires via a rapid heating process. Mater Sci Eng B 2011, 176: 87–91. 10.1016/j.mseb.2010.09.007View Article
- Wang X, Sun XY, Fairchild M, Hersee SD: Fabrication of GaN nanowire arrays by confined epitaxy. Appl Phys Lett 2006, 89: 233115. 10.1063/1.2402893View Article
- Navamathavan R, Ra YH, Song KY, Kim DW, Lee CR: Different growth behaviors of GaN nanowires grown with Au catalyst and Au + Ga solid solution nano-droplets on Si(111) substrates by using MOCVD. Curr Appl Phys 2011, 11: 77–81. 10.1016/j.cap.2010.06.022View Article
- Chen J, Xue CS: Catalytic growth of large-scale GaN nanowires. J Mater Eng Perform 2010, 19: 1054–1057. 10.1007/s11665-009-9574-8View Article
- Zhou ZH, Wu J, Li HD, Wang ZM: Field emission from in situ-grown vertically aligned SnO2nanowire arrays. Nanoscale Res Lett 2012, 7: 117. 10.1186/1556-276X-7-117View Article
- Ma CY, Zhou ZH, Wei H, Yang Z, Wang ZM, Zhang YF: Rapid large-scale preparation of ZnO nanowires for photocatalytic application. Nanoscale Res Lett 2011, 6: 536. 10.1186/1556-276X-6-536View Article
- Wang ZL, Song JH: Piezoelectric nanogenerators based on zinc oxide nanowire arrays. Science 2006, 312: 242–246. 10.1126/science.1124005View Article
- Wang XH, Li RB, Fan DH: Control growth of catalyst-free high-quality ZnO nanowire arrays on transparent quartz glass substrate by chemical vapor deposition. Appl Surf Sci 2011, 257: 2960–2964. 10.1016/j.apsusc.2010.10.100View Article
- Zhou ZH, Zhan CH, Wang YY, Su YJ, Yang Z, Zhang YF: Rapid mass production of ZnO nanowires by a modified carbothermal reduction method. Mater Lett 2011, 65: 832–835. 10.1016/j.matlet.2010.12.032View Article
- Khan R, Ra HW, Kim JT, Jang WS, Sharma D, Im YH: Nanojunction effects in multiple ZnO nanowire gas sensor. Sens Actuators B 2011, 150: 389–393.View Article
- Luo L, Sosnowchil BD, Lin LW: Room temperature fast synthesis of zinc oxide nanowires by inductive heating. Appl Phys Lett 2007, 90: 093101. 10.1063/1.2709618View Article
- Ramanathan S, Chen YC, Tzeng Y: Zinc oxide nanowire based field emitters. Physica E 2010, 43: 285–288. 10.1016/j.physe.2010.07.072View Article
- Wang FF, Cao L, Pan AL, Liu RB, Wang X, Zhu X, Wang HQ, Zou BS: Synthesis of tower-like ZnO structures and visible photoluminescence origins of varied-shaped ZnO nanostructures. J Phys Chem C 2007, 111: 7655–7660. 10.1021/jp067151uView Article
- Wu JJ, Liu SC: Low-temperature growth of well-aligned ZnO nanorods by chemical vapor deposition. Adv Mater 2002, 14: 215–218. 10.1002/1521-4095(20020205)14:3<215::AID-ADMA215>3.0.CO;2-JView Article
- Zhu G, Yang R, Wang S, Wang ZL: Flexible high-output nanogenerator based on lateral ZnO nanowire array. Nano Lett 2010, 10: 3151–3155. 10.1021/nl101973hView Article
- Zhang Z, Meng GW, Xu QL, Hu YM, Wu Q, Hu Z: Aligned ZnO nanorods with tunable size and field emission on native Si substrate achieved via simple electrodeposition. J Phys Chem C 2010, 114: 189–193. 10.1021/jp9087223View Article
- Breedon M, Rahmani MB, Keshmirii SH, Wlodarski W, Kalantarzadeh K: Aqueous synthesis of interconnected ZnO nanowires using spray pyrolysis deposited seed layers. Mater Lett 2010, 64: 291–294. 10.1016/j.matlet.2009.10.065View Article
- Sarkar S, Patra S, Bera SK, Paul GK, Ghosh R: Water repellent ZnO nanowire arrays synthesized by simple solvothermal technique. Mater Lett 2010, 64: 460–462. 10.1016/j.matlet.2009.11.047View Article
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.