本論文研究以原子力顯微術微影製作單一氧化鈦奈米點、成長具有氧化亞銅奈米粒子修飾的氧化鋅奈米線、以及紫外光與一氧化氮氣體感測方面的應用。
論文的第一部分，旨在單一氧化鈦奈米點的製作與其在紫外光感測方面的應用。實驗中先以原子力顯微術奈米機械力加工製備單一金屬鈦奈米線，並將其跨接於金電極的兩端。再利用原子力顯微術奈米氧化製作單一氧化鈦奈米點感測器。製作出的感測器分為歐姆型與蕭特基型兩種，對波長254奈米紫外光的靈敏度分別為0.25與320。蕭特基型感測器的反應時間與恢復時間也顯著地較為快速。
論文的第二部分，探討單一氧化鈦奈米點感測器在光活化與光恢復兩種方法下的一氧化氮氣體感測特性。發現尺寸小的奈米點具有較佳的感測性能，對於10 ppm濃度的一氧化氮氣體，響應值為31%，反應時間為91秒，恢復時間為184秒。此部分研究顯示單一氧化鈦奈米點氣體感測器和其他金屬氧化物奈米線感測器相比，也具有很大的應用潛力。
論文的第三部分，探討具有氧化亞銅奈米粒子修飾的氧化鋅奈米線的一氧化氮氣體感測特性。比較有修飾氧化亞銅奈米粒子與未修飾氧化亞銅奈米粒子的兩種氧化鋅奈米線感測器，對於1 ppm一氧化氮氣體的響應值，經修飾的感測器可達353%，為未修飾感測器的14.7倍。對60 ppb一氧化氮氣體的響應值可達8.5%，顯示其對低濃度的一氧化氮氣體感測應用深具潛力。

The scope of this thesis covers the fabrication of a single titanium oxide nanodot (ND) by atomic force microscopy (AFM) nanolithography, growth of Cu2O nanoparticle (NP) modified ZnO nanowires (NWs) and applications for ultraviolet (UV) light and NO gas sensing.
In the first part of thesis, we report on the fabrication of a single titanium oxide ND UV sensor by AFM nanolithography. A single titanium NW is first fabricated by AFM nanomachining and gold contact electrodes are then created by photolithography. By subsequent AFM nano-oxidation, a single titanium oxide ND sensor is produced. Two types of ND sensors, namely ohmic contact and Schottky contact, have been obtained and the sensitivities are around 0.25 and 320, respectively, under ultraviolet illumination. The rise and the reset times of the Schottky contact sensor are also significantly faster.
In the second part of thesis, gas sensing using the titanium oxide ND sensor is realized by the photo-activation and the photo-recovery approaches. It is found that a senor with a smaller ND has better performance than a larger one. A response of 31%, a response time of 91 s, and a recovery time of 184 s have been achieved at a concentration of 10 ppm for a ND with a size of around 80 nm. The present work demonstrates the potential application of single metal oxide NDs for gas sensing with performance that can be compared with metal oxide nanowire gas sensors.
In the third part of thesis, we report on the NO gas sensing performance of Cu2O nanoparticle (NP) modified ZnO nanowires (NWs) under ambient environment. ZnO NWs are grown on Si substrates using a solution method and then modified with Cu2O NPs by photoreduction. The response of the NP modified NWs sensor to 1 ppm NO gas is 353%, which is 14.7 times as high as that of unmodified NW sensor. A response of 8.5% has been achieved at 60 ppb, showing the good potential for low concentration NO sensing.

List of Figures III
List of Tables VII
Acknowledgments VIII
中文摘要 IX
Abstract XI
Chapter 1 Introduction 1
1.1 Metal Oxide Nanomaterials for Sensing Applications 1
1.2 UV Light Sensing Applications 2
1.3 NO Gas Sensing Applications 3
1.4 Motivation and Scope 4
Chapter 2 Literature Review 5
2.1 AFM Nanolithography 5
2.1.1 AFM Nanomachining 6
2.1.2 AFM Nano-Oxidation 7
2.2 UV Sensors Based on SMO Nanomaterials 9
2.3 Gas Sensors Based on SMO Nanomaterials 11
2.3.1 Photo-Activation and Photo-Recovery 13
2.3.2 Self-Heating 15
2.3.3 Surface Modification 16
Chapter 3 Experimental Instruments and Procedures 17
3.1 Experimental Instruments 17
3.1.1 Atomic Force Microscope 18
3.1.2 Scanning Electron Microscope 18
3.1.3 Transmission Electron Microscope 18
3.1.4 Auger Electron Spectrometer 19
3.1.5 E-Beam Evaporation System 19
3.1.6 Mask Aligner System 20
3.1.7 Wire Bonder 20
3.2 Experimental Procedures 22
3.2.1 Fabrication of Single Titanium Oxide Nanodot Sensors 22
3.2.2 Fabrication of ZnO Nanowires Sensors 23
3.2.3 UV Light Sensing 25
3.2.4 NO Gas Sensing by the Single TiOx ND 25
3.2.5 NO Gas Sensing by the Modified ZnO NWs 26
Chapter 4 Single Titanium Oxide Nanodot Ultraviolet Sensors 28
4.1 The TiOx Nanodot Fabricated by AFM 28
4.2 Schottky Contact and Ohmic Contact Sensors 31
4.3 UV Detection Properties 34
Chapter 5 NO Gas Sensing Using Single Titanium Oxide Nanodot Sensors 38
5.1 TiOx Nanodot Morphology 38
5.2 NO Gas Sensing Properties 41
5.3 Sensing Mechanism 53
Chapter 6 NO gas Sensing Using Cu2O Nanoparticle Modified ZnO Nanowires Sensors 57
6.1 ZnO Nanowires Morphology 57
6.2 NO Gas Sensing Properties 59
6.3 Sensing Mechanism 63
Chapter 7 Conclusions 65
References 67
Curriculum Vitae 83
Publication 84

[1] Cheng Y, Xiong P, Yun CS, Strouse GF, Zheng JP, Yang RS, et al. Mechanism and optimization of pH sensing using SnO2 nanobelt field effect transistors. Nano Letters 2008;8:4179-84.
[2] Menzel A, Subannajui K, Güder F, Moser D, Paul O, Zacharias M. Multifunctional ZnO-nanowire-based sensor. Advanced Functional Materials 2011;21:4342-8.
[3] Chang S-P, Chang S-J, Lu C-Y, Li M-J, Hsu C-L, Chiou Y-Z, et al. A ZnO nanowire-based humidity sensor. Superlattices and Microstructures 2010;47:772-8.
[4] Hsu C-L, Tsai J-Y, Hsueh T-J. Ethanol gas and humidity sensors of CuO/Cu2O composite nanowires based on a Cu through-silicon via approach. Sensors and Actuators B: Chemical 2016;224:95-102.
[5] Chen X, Wong CKY, Yuan CA, Zhang G. Nanowire-based gas sensors. Sensors and Actuators B: Chemical 2013;177:178-95.
[6] Comini E, Sberveglieri G. Metal oxide nanowires as chemical sensors. Materials Today 2010;13:36-44.
[7] Ramgir NS, Yang Y, Zacharias M. Nanowire-based sensors. Small 2010;6:1705-22.
[8] Choi KJ, Jang HW. One-dimensional oxide nanostructures as gas-sensing materials: Review and issues. Sensors 2010;10:4083.
[9] Choi A, Kim K, Jung HI, Lee SY. ZnO nanowire biosensors for detection of biomolecular interactions in enhancement mode. Sensors and Actuators B-Chemical 2010;148:577-82.
[10] Hu Y, Zhou J, Yeh P-H, Li Z, Wei T-Y, Wang ZL. Supersensitive, fast-response nanowire sensors by using Schottky contacts. Advanced Materials 2010;22:3327-32.
[11] Korotcenkov G. Metal oxides for solid-state gas sensors: What determines our choice? Materials Science and Engineering: B 2007;139:1-23.
[12] Wang C, Yin L, Zhang L, Xiang D, Gao R. Metal oxide gas sensors: Sensitivity and influencing factors. Sensors 2010;10:2088.
[13] Monroy E, Omnes F, Calle F. Wide-bandgap semiconductor ultraviolet photodetectors. Semiconductor Science and Technology 2003;18:R33-R51.
[14] Kind H, Yan HQ, Messer B, Law M, Yang PD. Nanowire ultraviolet photodetectors and optical switches. Advanced Materials 2002;14:158.
[15] Soci C, Zhang A, Xiang B, Dayeh SA, Aplin DPR, Park J, et al. ZnO nanowire UV photodetectors with high internal gain. Nano Letters 2007;7:1003-9.
[16] Liu K, Sakurai M, Liao M, Aono M. Giant improvement of the performance of ZnO nanowire photodetectors by Au nanoparticles. Journal of Physical Chemistry C 2010;114:19835-9.
[17] Cheng G, Wu X, Liu B, Li B, Zhang X, Du Z. ZnO nanowire Schottky barrier ultraviolet photodetector with high sensitivity and fast recovery speed. Applied Physics Letters 2011;99:203105.
[18] Tzeng S-K, Hon M-H, Leu I-C. Improving the performance of a zinc oxide nanowire ultraviolet photodetector by adding silver nanoparticles. Journal of The Electrochemical Society 2012;159:H440-H3.
[19] Li C, Bando Y, Liao M, Koide Y, Golberg D. Visible-blind deep-ultraviolet Schottky photodetector with a photocurrent gain based on individual Zn2GeO4 nanowire. Applied Physics Letters 2010;97:161102.
[20] Zhou J, Gu YD, Hu YF, Mai WJ, Yeh PH, Bao G, et al. Gigantic enhancement in response and reset time of ZnO UV nanosensor by utilizing Schottky contact and surface functionalization. Applied Physics Letters 2009;94.
[21] Chen RS, Chen CA, Tsai HY, Wang WC, Huang YS. Photoconduction properties in single-crystalline titanium dioxide nanorods with ultrahigh normalized gain. The Journal of Physical Chemistry C 2012;116:4267-72.
[22] Tsai T-Y, Chang S-J, Weng W-Y, Hsu C-L, Wang S-H, Chiu C-J, et al. A visible-blind TiO2 nanowire photodetector. Journal of The Electrochemical Society 2012;159:J132-J5.
[23] Hu L, Yan J, Liao M, Wu L, Fang X. Ultrahigh external quantum efficiency from thin SnO2 nanowire ultraviolet photodetectors. Small 2011;7:1012-7.
[24] Zhang D, Li C, Han S, Liu X, Tang T, Jin W, et al. Ultraviolet photodetection properties of indium oxide nanowires. Applied Physics A 2003;77:163-6.
[25] Niranjan Ramgir ND, Manmeet Kaur, S. Kailasaganapathi, Anil K. Debnath, D.K. Aswal, S.K. Gupta. Metal oxide nanowires for chemiresistive gas sensors: Issues, challenges and prospects. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2013;439:101-16.
[26] Liu X, Cheng S, Liu H, Hu S, Zhang D, Ning H. A survey on gas sensing technology. Sensors 2012;12:9635.
[27] Chiu S-W, Tang K-T. Towards a chemiresistive sensor-integrated electronic nose: A review. Sensors 2013;13:14214.
[28] Franke ME, Koplin TJ, Simon U. Metal and metal oxide nanoparticles in chemiresistors: Does the Nanoscale Matter? Small 2006;2:36-50.
[29] Hernandez-Ramirez F, Prades JD, Tarancon A, Barth S, Casals O, Jiménez–Diaz R, et al. Portable microsensors based on individual SnO2 nanowires. Nanotechnology 2007;18:495501.
[30] Fine GF, Cavanagh LM, Afonja A, Binions R. Metal oxide semi-conductor gas sensors in environmental monitoring. Sensors 2010;10:5469.
[31] Afzal A, Cioffi N, Sabbatini L, Torsi L. NOx sensors based on semiconducting metal oxide nanostructures: Progress and perspectives. Sensors and Actuators B: Chemical 2012;171–172:25-42.
[32] Wetchakun K, Samerjai T, Tamaekong N, Liewhiran C, Siriwong C, Kruefu V, et al. Semiconducting metal oxides as sensors for environmentally hazardous gases. Sensors and Actuators B: Chemical 2011;160:580-91.
[33] Di Natale C, Paolesse R, Martinelli E, Capuano R. Solid-state gas sensors for breath analysis: A review. Analytica Chimica Acta 2014;824:1-17.
[34] Guo D, Zhang D, Li N, Zhang L, Yang J. A novel breath analysis system based on electronic olfaction. IEEE Transactions on Biomedical Engineering 2010;57:2753-63.
[35] Righettoni M, Amann A, Pratsinis SE. Breath analysis by nanostructured metal oxides as chemo-resistive gas sensors. Materials Today 2015;18:163-71.
[36] BOC gases, material safety data sheet, 1996.
[37] Frandsen U, LopezFigueroa M, Hellsten Y. Localization of nitric oxide synthase in human skeletal muscle. Biochem Biophys Res Commun 1996;227:88-93.
[38] Puckett JL, George SC. Partitioned exhaled nitric oxide to non-invasively assess asthma. Respir Physiol Neuro 2008;163:166-77.
[39] Maziak W, Loukides S, Culpitt S, Sullivan P, Kharitonov SA, Barnes PJ. Exhaled nitric oxide in chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1998;157:998-1002.
[40] Cristescu SM, Mandon J, Harren FJM, Meriläinen P, Högman M. Methods of NO detection in exhaled breath. Journal of Breath Research 2013;7:017104.
[41] Parthangal PM, Cavicchi RE, Zachariah MR. A universal approach to electrically connecting nanowire arrays using nanoparticles - application to a novel gas sensor architecture. Nanotechnology 2006;17:3786-90.
[42] Verma VP, Das S, Hwang S, Choi H, Jeon M, Choi W. Nitric oxide gas sensing at room temperature by functionalized single zinc oxide nanowire. Mater Sci Eng B-Adv Funct Solid-State Mater 2010;171:45-9.
[43] Singh N, Yan CY, Lee PS, Comini E. Sensing properties of different classes of gases based on the nanowire-electrode junction barrier modulation. Nanoscale 2011;3:1760-5.
[44] Park S, An S, Mun Y, Lee C. UV-enhanced NO2 gas sensing properties of SnO2-core/ZnO-shell nanowires at room temperature. ACS Applied Materials & Interfaces 2013;5:4285-92.
[45] Shaalan NM, Yamazaki T, Kikuta T. NO2 response enhancement and anomalous behavior of n-type SnO2 nanowires functionalized by Pd nanodots. Sensors and Actuators B: Chemical 2012;166–167:671-7.
[46] Xu S, Gao J, Wang L, Kan K, Xie Y, Shen P, et al. Role of the heterojunctions in In2O3-composite SnO2 nanorod sensors and their remarkable gas-sensing performance for NOx at room temperature. Nanoscale 2015;7:14643-51.
[47] Gogurla N, Sinha AK, Santra S, Manna S, Ray SK. Multifunctional Au-ZnO plasmonic nanostructures for enhanced UV photodetector and room temperature NO sensing devices. Sci Rep 2014;4.
[48] Mun Y, Park S, An S, Lee C, Kim HW. NO2 gas sensing properties of Au-functionalized porous ZnO nanosheets enhanced by UV irradiation. Ceramics International 2013;39:8615-22.
[49] Yang Z, Guo L, Zu B, Guo Y, Xu T, Dou X. CdS/ZnO core/shell nanowire-built films for enhanced photodetecting and optoelectronic gas-sensing applications. Advanced Optical Materials 2014;2:738-45.
[50] Na CW, Woo H-S, Kim I-D, Lee J-H. Selective detection of NO2 and C2H5OH using a Co3O4-decorated ZnO nanowire network sensor. Chemical Communications 2011;47:5148-50.
[51] Bekermann D, Gasparotto A, Barreca D, Maccato C, Comini E, Sada C, et al. Co3O4/ZnO nanocomposites: from plasma synthesis to gas sensing applications. ACS Applied Materials & Interfaces 2012;4:928-34.
[52] Fan S-W, Srivastava AK, Dravid VP. Nanopatterned polycrystalline ZnO for room temperature gas sensing. Sensors and Actuators B-Chemical 2010;144:159-63.
[53] Cai Z-X, Li H-Y, Yang X-N, Guo X. NO sensing by single crystalline WO3 nanowires. Sensors and Actuators B: Chemical 2015;219:346-53.
[54] Chang B-Y, Wang C-Y, Lai H-F, Wu R-J, Chavali M. Evaluation of Pt/In2O3–WO3 nano powder ultra-trace level NO gas sensor. Journal of the Taiwan Institute of Chemical Engineers 2014;45:1056-64.
[55] Moon HG, Choi YR, Shim Y-S, Choi K-I, Lee J-H, Kim J-S, et al. Extremely sensitive and selective NO probe based on villi-like WO3 nanostructures for application to exhaled breath analyzers. ACS Applied Materials & Interfaces 2013;5:10591-6.
[56] Rai P, Khan R, Raj S, Majhi SM, Park K-K, Yu Y-T, et al. Au@Cu2O core-shell nanoparticles as chemiresistors for gas sensor applications: effect of potential barrier modulation on the sensing performance. Nanoscale 2014;6:581-8.
[57] Deng S, Tjoa V, Fan HM, Tan HR, Sayle DC, Olivo M, et al. Reduced graphene oxide conjugated Cu2O nanowire mesocrystals for high-performance NO2 gas sensor. Journal of the American Chemical Society 2012;134:4905-17.
[58] Xu S, Wang ZL. One-dimensional ZnO nanostructures: Solution growth and functional properties. Nano Research 2011;4:1013-98.
[59] Chen C, Li Z, Lin H, Wang G, Liao J, Li M, et al. Enhanced visible light photocatalytic performance of ZnO nanowires integrated with CdS and Ag2S. Dalton Transactions 2016;45:3750-8.
[60] Williams FJ, Palermo A, Tikhov MS, Lambert RM. First demonstration of in situ electrochemical control of a base metal catalyst:  Spectroscopic and kinetic study of the CO + NO reaction over Na-promoted Cu. The Journal of Physical Chemistry B 1999;103:9960-6.
[61] Zhang G, Liu M. Effect of particle size and dopant on properties of SnO2-based gas sensors. Sensors and Actuators B: Chemical 2000;69:144-52.
[62] Shen G, Chen P-C, Ryu K, Zhou C. Devices and chemical sensing applications of metal oxide nanowires. Journal of Materials Chemistry 2009;19:828-39.
[63] Yang P, Yan R, Fardy M. Semiconductor nanowire: What’s next? Nano Letters 2010;10:1529-36.
[64] Hobbs RG, Petkov N, Holmes JD. Semiconductor nanowire fabrication by bottom-up and top-down paradigms. Chemistry of Materials 2012;24:1975-91.
[65] Soh HT, Guarini KW, Quate CF. Scanning probe lithography: Springer US; 2013.
[66] Chen YJ, Hsu JH, Lin HN. Fabrication of metal nanowires by atomic force microscopy nanoscratching and lift-off process. Nanotechnology 2005;16:1112-5.
[67] Dagata JA, Schneir J, Harary HH, Evans CJ, Postek MT, Bennett J. Modification of hydrogen‐passivated silicon by a scanning tunneling microscope operating in air. Applied Physics Letters 1990;56:2001-3.
[68] Day HC, Allee DR. Selective area oxidation of silicon with a scanning force microscope. Applied Physics Letters 1993;62:2691-3.
[69] Snow ES, Campbell PM. AFM fabrication of sub-10-nanometer metal-oxide devices with in situ control of electrical properties. Science 1995;270:1639-41.
[70] Matsumoto K, Ishii M, Segawa K, Oka Y, Vartanian BJ, Harris JS. Room temperature operation of a single electron transistor made by the scanning tunneling microscope nanooxidation process for the TiOx/Ti system. Applied Physics Letters 1996;68:34-6.
[71] Delacour C, Claudon J, Poizat J-P, Pannetier B, Bouchiat V, Espiau de Lamaestre R, et al. Superconducting single photon detectors made by local oxidation with an atomic force microscope. Applied Physics Letters 2007;90:191116.
[72] Siles PF, Archanjo BS, Baptista DL, Pimentel VL, Joshua J, Neves BRA, et al. Nanoscale lateral switchable rectifiers fabricated by local anodic oxidation. Journal of Applied Physics 2011;110:024511.
[73] Li Z, Wu M, Liu T, Wu C, Jiao Z, Zhao B. Preparation of TiO2 nanowire gas nanosensor by AFM anode oxidation. Ultramicroscopy 2008;108:1334-7.
[74] Archanjo BS, Silveira GV, goncalves A-MB, Alves DCB, Ferlauto AS, Lacerda RG, et al. Fabrication of gas nanosensors and microsensors via local anodic oxidation. Langmuir 2009;25:602-5.
[75] Archanjo BS, Siles PF, Oliveira C, Baptista DL, Neves BRA. Characterization of metal oxide-based gas nanosensors and microsensors fabricated via local anodic oxidation using atomic force microscopy. Advances in Materials Science and Engineering 2013.
[76] Bao J, Shalish I, Su Z, Gurwitz R, Capasso F, Wang X, et al. Photoinduced oxygen release and persistent photoconductivity in ZnO nanowires. Nanoscale Research Letters 2011;6:1-7.
[77] Joondong K, Ju-Hyung Y, Chang Hyun K, Yun Chang P, Ju Yeon W, Jeunghee P, et al. ZnO nanowire-embedded Schottky diode for effective UV detection by the barrier reduction effect. Nanotechnology 2010;21:115205.
[78] Wei T-Y, Yeh P-H, Lu S-Y, Lin-Wang Z. Gigantic enhancement in sensitivity using Schottky contacted nanowire nanosensor. Journal of the American Chemical Society 2009;131:17690-5.
[79] Law M, Kind H, Messer B, Kim F, Yang PD. Photochemical sensing of NO2 with SnO2 nanoribbon nanosensors at room temperature. Angew Chem-Int Edit 2002;41:2405-8.
[80] Kolmakov A, Moskovits M. Chemical sensing and catalysis by one-dimensional metal-oxide nanostructures. Ann Rev Mater Res 2004;34:151-80.
[81] Manno D, Micocci G, Serra A, Di Giulio M, Tepore A. Structural and electrical properties of In2O3-SeO2 mixed oxide thin films for gas sensing applications. J Appl Phys 2000;88:6571-7.
[82] Kim I-D, Rothschild A, Tuller HL. Advances and new directions in gas-sensing devices. Acta Materialia 2013;61:974-1000.
[83] Choi S-W, Kim SS. Room temperature CO sensing of selectively grown networked ZnO nanowires by Pd nanodot functionalization. Sensors and Actuators B: Chemical 2012;168:8-13.
[84] Law M, Kind H, Messer B, Kim F, Yang P. Photochemical sensing of NO2 with SnO2 nanoribbon nanosensors at room temperature. Angewandte Chemie 2002;114:2511-4.
[85] Fan S-W, Srivastava AK, Dravid VP. UV-activated room-temperature gas sensing mechanism of polycrystalline ZnO. Applied Physics Letters 2009;95:142106.
[86] Korotcenkov G, Cho BK. Instability of metal oxide-based conductometric gas sensors and approaches to stability improvement (short survey). Sensors and Actuators B: Chemical 2011;156:527-38.
[87] Comini E, Cristalli A, Faglia G, Sberveglieri G. Light enhanced gas sensing properties of indium oxide and tin dioxide sensors. Sensors and Actuators B: Chemical 2000;65:260-3.
[88] Comini E, Faglia G, Sberveglieri G. UV light activation of tin oxide thin films for NO2 sensing at low temperatures. Sensors and Actuators B: Chemical 2001;78:73-7.
[89] Prades JD, Jimenez-Diaz R, Hernandez-Ramirez F, Barth S, Cirera A, Romano-Rodriguez A, et al. Equivalence between thermal and room temperature UV light-modulated responses of gas sensors based on individual SnO2 nanowires. Sensors and Actuators B: Chemical 2009;140:337-41.
[90] Prades JD, Jimenez-Diaz R, Manzanares M, Hernandez-Ramirez F, Cirera A, Romano-Rodriguez A, et al. A model for the response towards oxidizing gases of photoactivated sensors based on individual SnO2 nanowires. Physical Chemistry Chemical Physics 2009;11:10881-9.
[91] Mishra S, Ghanshyam C, Ram N, Bajpai RP, Bedi RK. Detection mechanism of metal oxide gas sensor under UV radiation. Sensors and Actuators B: Chemical 2004;97:387-90.
[92] Lu G, Xu J, Sun J, Yu Y, Zhang Y, Liu F. UV-enhanced room temperature NO2 sensor using ZnO nanorods modified with SnO2 nanoparticles. Sensors and Actuators B: Chemical 2012;162:82-8.
[93] Zhang D, Liu Z, Li C, Tang T, Liu X, Han S, et al. Detection of NO2 down to ppb levels using individual and multiple In2O3 nanowire devices. Nano Letters 2004;4:1919-24.
[94] Verma VP, Das S, Hwang S, Choi H, Jeon M, Choi W. Nitric oxide gas sensing at room temperature by functionalized single zinc oxide nanowire. Materials Science and Engineering: B 2010;171:45-9.
[95] Prades JD, Jimenez-Diaz R, Hernandez-Ramirez F, Barth S, Cirera A, Romano-Rodriguez A, et al. Ultralow power consumption gas sensors based on self-heated individual nanowires. Applied Physics Letters 2008;93:123110.
[96] Prades JD, Jimenez-Diaz R, Hernandez-Ramirez F, Cirera A, Romano-Rodriguez A, Morante JR. Harnessing self-heating in nanowires for energy efficient, fully autonomous and ultra-fast gas sensors. Sensors and Actuators B: Chemical 2010;144:1-5.
[97] Evgheni S, Serghei D, Bradley B, Joshua C, Victor S, Andrei K. Evidence of the self-heating effect on surface reactivity and gas sensing of metal oxide nanowire chemiresistors. Nanotechnology 2008;19:355502.
[98] Hernandez-Ramirez F, Prades JD, Jimenez-Diaz R, Fischer T, Romano-Rodriguez A, Mathur S, et al. On the role of individual metal oxide nanowires in the scaling down of chemical sensors. Physical Chemistry Chemical Physics 2009;11:7105-10.
[99] Hernandez-Ramirez F, Tarancon A, Casals O, Pellicer E, Rodriguez J, Romano-Rodriguez A, et al. Electrical properties of individual tin oxide nanowires contacted to platinum electrodes. Physical Review B 2007;76:085429.
[100] Miller DR, Akbar SA, Morris PA. Nanoscale metal oxide-based heterojunctions for gas sensing: A review. Sensors and Actuators B: Chemical 2014;204:250-72.
[101] Rai P, Majhi SM, Yu Y-T, Lee J-H. Noble metal@metal oxide semiconductor core@shell nano-architectures as a new platform for gas sensor applications. RSC Advances 2015;5:76229-48.
[102] Kolmakov A, Chen X, Moskovits M. Functionalizing nanowires with catalytic nanoparticles for gas sensing application. Journal of Nanoscience and Nanotechnology 2008;8:111-21.
[103] Kolmakov A, Klenov DO, Lilach Y, Stemmer S, Moskovits M. Enhanced gas sensing by individual SnO2 nanowires and nanobelts functionalized with Pd catalyst particles. Nano Letters 2005;5:667-73.
[104] Aswal DK, Gupta SK. Science and technology of chemiresistor gas sensors: Nova Science Publishers; 2007.
[105] Lin H-Y, Chen H-A, Lin H-N. Fabrication of a single metal nanowire connected with dissimilar metal electrodes and its application to chemical sensing. Analytical Chemistry 2008;80:1937-41.
[106] Chang Y-H, Chiang M-Y, Chang J-H, Lin H-N. Enhanced visible light photocatalysis of cuprous oxide nanoparticle modified zinc oxide nanowires. Materials Letters 2015;138:85-8.
[107] Fang T-H, Wang TH, Wu K-T. Local oxidation of titanium films by non-contact atomic force microscopy. Microelectronic Engineering 2008;85:1616-23.
[108] Zhong N, Shima H, Akinaga H. Rectifying characteristic of Pt/TiOx/metal/Pt controlled by electronegativity. Applied Physics Letters 2010;96:042107.
[109] Xue H, Kong X, Liu Z, Liu C, Zhou J, Chen W, et al. TiO2 based metal-semiconductor-metal ultraviolet photodetectors. Applied Physics Letters 2007;90:201118.
[110] Hong L-Y, Lin H-N. Fabrication of single titanium oxide nanodot ultraviolet sensors by atomic force microscopy nanolithography. Sensors and Actuators A: Physical 2015;232:94-8.
[111] Zou X, Fan H, Tian Y, Yan S. Synthesis of Cu2O/ZnO hetero-nanorod arrays with enhanced visible light-driven photocatalytic activity. CrystEngComm 2014;16:1149-56.