本研究針對兩種金屬氧化物半導體材料，分別是化學氣相沉積法(CVD)成長之n-type氧化鋅奈米線以及p-type氧化亞錫奈米線、利用電子束微影技術製作奈米元件進行室溫氨氣感測性質分析。在分析上分別以掃描式電子顯微鏡(Scanning Electron Microscopy, SEM)和穿透式電子顯微鏡(Transmission Electron Microscopy, TEM)瞭解氧化鋅以及氧化亞錫奈米結構之表面形貌與微結構。利用X射線光電子能譜(X-ray photoelectron spectroscopy, XPS) 探討奈米線表面性質以及鍵結。結果發現氧化鋅奈米線比起氧化亞錫奈米線含有較多的HO- 鍵結，百分比分別為79 %、22 %，意味著容易含有較多的水氣。藉由及時記錄奈米線感測過程的電流變化，探討在氨氣吸附在奈米線上的機制，並推算吸附/脫附反應速率常數，可以發現在氨氣進入腔體後，氧化鋅的電導增加，氧化亞錫電導則是下降。而且氧化鋅對氨氣所需要的反應時間比氧化亞錫短，例如同樣在70 ppm下，大約短14秒，因此氧化鋅具有比較大的吸附速率常數，可以更快地偵測氨氣。

This study is to investigate gas sensing properties of individual ZnO and SnO nanowires grown by chemical vapor deposition (CVD). To measure NH3 gas sensing properties in room temperature, as-grown single nanowires were placed on a chip to fabricate the device with the e-beam lithography technology.
The morphology and microstructure of the ZnO and SnO nanostructures were characterized by scanning electron microscopy and transmission electron microscopy. With X-ray photoelectron spectroscopy, we can investigate the surface properties and bonding of the nanowires.
From the results, the ZnO nanowires form more OH- bonding than SnO nanowires. The percentage of OH- bonding of ZnO and SnO are 79 % and 22 %, respectively. It means that water adsorption on ZnO nanowires is easier than that on SnO nanowires. By time dependence measurement, the sensing mechanism has been analyzed. The adsorption rate constants and desorption rate constants have also been calculated. The conductance of ZnO increases but that of SnO decreases when NH3 injection into the chamber. We can find that the response time of ZnO nanowires is shorter than that of SnO nanowires (about 14 seconds shorter in 70 ppm NH3) which means that ZnO nanowires have a larger adsorption rate constant and can detect NH3 fast.

[1] C. Wang, L. Yin, L. Zhang, D. Xiang, and R. Gao, "Metal oxide gas sensors: sensitivity and influencing factors," Sensors (Basel), vol. 10, pp. 2088-106, 2010.
[2] U. Ozgur, Y. I. Alivov, C. Liu, A. Teke, M. A. Reshchikov, S. Dogan, V. Avrutin, S. J. Cho, and H. Morkoc, "A comprehensive review of ZnO materials and devices," Journal of Applied Physics, vol. 98, Aug 15 2005.
[3] F. A. Kroger, The chemistry of imperfect crystals, 2nd rev. ed. ed.: Amsterdam : North-Holland Pub. Co. ; New York : American Elsevier, , 1964.
[4] X. Q. Pan and L. Fu, "Oxidation and phase transitions of epitaxial tin oxide thin films on (1̄012) sapphire," Journal of Applied Physics, vol. 89, p. 6048, 2001.
[5] Y. W. Li, Y. Li, T. Cui, L. J. Zhang, Y. M. Ma, and G. T. Zou, "The pressure-induced phase transition in SnO: a first-principles study," Journal of Physics: Condensed Matter, vol. 19, p. 425230, 2007.
[6] A. Togo, F. Oba, I. Tanaka, and K. Tatsumi, "First-principles calculations of native defects in tin monoxide," Physical Review B, vol. 74, 2006.
[7] R. Sivaramasubramaniam, M. R. Muhamad, and S. Radhakrishna, "OPTICAL-PROPERTIES OF ANNEALED TIN(II) OXIDE IN DIFFERENT AMBIENTS," Physica Status Solidi a-Applied Research, vol. 136, pp. 215-222, Mar 1993.
[8] F.-S. Tsai, S.-J. Wang, Y.-C. Tu, Y.-W. Hsu, C.-Y. Kuo, Z.-S. Lin, and R.-M. Ko, "Preparation of p-SnO/n-ZnO Heterojunction Nanowire Arrays and Their Optoelectronic Characteristics under UV Illumination," Applied Physics Express, vol. 4, p. 025002, 2011.
[9] X. Xu, M. Ge, K. Ståhl, and J. Z. Jiang, "Growth mechanism of cross-like SnO structure synthesized by thermal decomposition," Chemical Physics Letters, vol. 482, pp. 287-290, 2009.
[10] Z. Wang and Z. Pan, "Junctions and Networks of SnO Nanoribbons," ADVANCED MATERIALS, vol. 14, pp. 1029-+, 2002.
[11] Z.-j. Jia, L.-p. Zhu, G.-h. Liao, Y. Yu, and Y.-w. Tang, "Preparation and characterization of SnO nanowhiskers," Solid State Communications, vol. 132, pp. 79-82, 2004.
[12] H. Uchiyama and H. Imai, "Matrix-Mediated Formation of Hierarchically Structured SnO Crystals As Intermediates between Single Crystals and Polycrystalline Aggregates," LANGMUIR, vol. 24, pp. 9038-9042, 2008.
[13] M. Orlandi, E. Leite, R. Aguiar, J. Bettini, and E. Longo, "Growth of SnO Nanobelts and Dendrites by a Self-Catalytic VLS Process," JOURNAL OF PHYSICAL CHEMISTRY B vol. 110, pp. 6621-6625, 2006.
[14] S. R. Morrison, The chemical physics of surfaces. New York: Plenum Press, 1990.
[15] H. E. N. E. L. STEPHEBNR UNAUERP, "Adsorption of Gases in Multimolecular Layers," JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 60, pp. 309-319, 1938.
[16] S. D. Brunauer, LS ; Deming, WE ; Teller, E, "On a theory of the van der Waals adsorption of gases," JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 62, pp. 1723-1732, 1940.
[17] H. P. Boehm, "Chemical Identification of Surface Groups," Advances in Catalysis, vol. 16, pp. 179-274, 1966.
[18] M. D. Batzill, U, "The surface and materials science of tin oxide," PROGRESS IN SURFACE SCIENCE, vol. 79, pp. 47-154, 2005.
[19] S. M. Sze, Semiconductor sensors vol. 28. John Wiley & Sons, New York: Microelectronics Journal, 1994.
[20] P. B. Weisz, "Effects of Electronic Charge Transfer between Adsorbate and Solid on Chemisorption and Catalysis," The Journal of Chemical Physics, vol. 21, p. 1531, 1953.
[21] D. KOHL, "Surface processes in the detection of reducing gases with SnO2-based devices.pdf>," Sensors and Actuators A: Physical, vol. 18, pp. 71-113, 1989.
[22] M. Batzill and U. Diebold, "The surface and materials science of tin oxide," Progress in Surface Science, vol. 79, pp. 47-154, 2005.
[23] N. W. Barsan, U "Conduction model of metal oxide gas sensors," JOURNAL OF ELECTROCERAMICS, vol. 7, pp. 143-167, 2001.
[24] Y. Z. A. Kolmakov, G. Cheng, M. Moskovits, "Detection of CO and O2 Using Tin Oxide Nanowire Sensors," Advanced Materials, vol. 15, pp. 997-1000, 2003.
[25] B. J. Hansen, N. Kouklin, G. Lu, I.-K. Lin, and J. Chen, "Transport, analyte detection, and opto-electronic response of p-type CuO nanowires," JOURNAL OF PHYSICAL CHEMISTRY C, vol. 114, pp. 2440-2447, 2010.
[26] T. SEIYAMA, A. KATO, K. FUJIISHI, and M. NAGATANI, "A New Detector for Gaseous Components Using Semiconductive Thin Films," ANALYTICAL CHEMISTRY, vol. 34, pp. 1502-1503, 1962.
[27] M. TAKATA, D. TSUBONE, and H. YANAGIDA, "Dependence of Electrical Conductivity of ZnO on Degree of Sintering," JOURNAL OF THE AMERICAN CERAMIC SOCIETY, vol. 59, pp. 4-8, 1976.
[28] S. P. S. Arya, A. D'Amico, and E. Verona, "Study of sputtered ZnOPd thin films as solid state H2 and NH3 gas sensors," Thin Solid Films, vol. 157, pp. 169-174, 1988.
[29] G. Sberveglieri, S. GROPPELLI, P. NELLI, A. TINTINELLI, and G. GIUNTA, "A novel method for the preparation of NH3 sensors based on ZnO-In thin films," SENSORS AND ACTUATORS B-CHEMICAL, vol. 25, pp. 588-590, 1995.
[30] J. X. Wang, X. W. Sun, Y. Yang, H. Huang, Y. C. Lee, O. K. Tan, and L. Vayssieres, "Hydrothermally grown oriented ZnO nanorod arrays for gas sensing applications," Nanotechnology, vol. 17, pp. 4995-4998, 2006.
[31] J. B. K. Law and J. T. L. Thong, "Improving the NH3 gas sensitivity of ZnO nanowire sensors by reducing the carrier concentration," Nanotechnology, vol. 19, 2008.
[32] C. S. Rout, M. Hegde, A. Govindaraj, and C. N. R. Rao, "Ammonia sensors based on metal oxide nanostructures," Nanotechnology, vol. 18, p. 205504, 2007.
[33] C. C. Li, Z. F. Du, L. M. Li, H. C. Yu, Q. Wan, and T. H. Wang, "Surface-depletion controlled gas sensing of ZnO nanorods grown at room temperature," Applied Physics Letters, vol. 91, p. 032101, 2007.
[34] W. An, X. Wu, and X. C. Zeng, "Adsorption of O2, H2, CO, NH3, and NO2 on ZnO Nanotube A Density Functional Theory Study," JOURNAL OF PHYSICAL CHEMISTRY C, vol. 112, pp. 5747-5755, 2008.
[35] 黃博建, "銦摻雜及未摻雜之氧化鋅奈米線及奈米緞帶熱電性質之研究," 國立成功大學 碩士論文, 2012.
[36] 汪建民, "材料分析 Material Analysis," 1998.
[37] J. F. Moulder, J. Chastain, and R. C. King, Handbook of x-ray photoelectron spectroscopy, 1995.
[38] T. BARR, " RECENT ADVANCES IN X-RAY PHOTOELECTRON-SPECTROSCOPY STUDIES OF OXIDES " JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS, vol. 9, pp. 1793-1805, 1991.
[39] M. Chen, X. Wang, Y. Yu, Z. Pei, X. Bai, C. Sun, R. Huang, and L. Wen, "X-ray photoelectron spectroscopy and auger electron spectroscopy studies of Al-doped ZnO films," APPLIED SURFACE SCIENCE, vol. 158, pp. 134-140, 2000.
[40] P.-T. Hsieh, Y.-C. Chen, K.-S. Kao, and C.-M. Wang, "Luminescence mechanism of ZnO thin film investigated by XPS measurement," APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, vol. 90, pp. 317-321 2008.
[41] S. Kumar, M. Bhatnagar, and K. L. Chopra, "Effect of hydrogen plasma treatment on transparent conducting oxides OH-," Applied Physics Letters, vol. 49, pp. 394-396, 1986.
[42] H. Xu, R. Q. Zhang, and S. Y. Tong, "Interaction of O_{2}, H_{2}O, N_{2}, and O_{3} with stoichiometric and reduced ZnO(101[over ¯]0) surface," Physical Review B, vol. 82, 2010.
[43] Y. Ogo, H. Hiramatsu, K. Nomura, H. Yanagi, T. Kamiya, M. Kimura, M. Hirano, and H. Hosono, "Tin monoxide as an s-orbital-based p-type oxide semiconductor - Electronic structures and TFT application," PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, vol. 206, pp. 2187-2191, 2009.
[44] B. Murray, E. Walter, and R. Penner, "Amine Vapor Sensing with Silver Mesowires," NANO LETTERS, vol. 4, pp. 665-670, 2004.
[45] A. A. Talin, L. L. Hunter, F. o. Léonard, and B. Rokad, "Large area, dense silicon nanowire array chemical sensors," Applied Physics Letters, vol. 89, p. 153102, 2006.
[46] D. Zhang, C. Li, X. Liu, S. Han, T. Tang, and C. Zhou, "Doping dependent NH[sub 3] sensing of indium oxide nanowires," Applied Physics Letters, vol. 83, p. 1845, 2003.
[47] G. Wang, Y. Ji, X. Yang, P.-I. Gouma, and M. Dudley, "Fabrication and Characterization of Polycrystalline WO3 Nanofibers and Their Application for Ammonia Sensing," JOURNAL OF PHYSICAL CHEMISTRY B, vol. 110, pp. 23777-23782, 2006.
[48] J. B. Law and J. T. Thong, "Improving the NH(3) gas sensitivity of ZnO nanowire sensors by reducing the carrier concentration," Nanotechnology, vol. 19, p. 205502, May 21 2008.
[49] F. Shao, F. Hernandez-Ramirez, J. D. Prades, J. R. Morante, and N. Lopez, "Assessment and Modeling of NH3-SnO2 Interactions using Individual Nanowires," Procedia Engineering, vol. 47, pp. 293-297, 2012.
[50] M. J. Madou and S. R. Morrison, Chemical sensing with solid state devices Boston: Academic Press, 1989.
[51] D. Manno, G. Micocci, A. Serra, M. Di Giulio, and A. Tepore, "Structural and electrical properties of In[sub 2]O[sub 3]–SeO[sub 2] mixed oxide thin films for gas sensing applications," Journal of Applied Physics, vol. 88, p. 6571, 2000.
[52] A. Kolmakov and M. Moskovits, "Chemical Sensing and Catalysis by One-Dimensional Metal-Oxide Nanostructures," Annual Review of Materials Research, vol. 34, pp. 151-180, 2004.