近年來，科技的發達造成環境和健康的危害，也漸漸地成為人們關注的焦點，因此氣體感測器已被廣泛應用於化學工業、農業、漁業、食品工業和環境監控等領域，氧化鎳氣體感測器具有良好的化學穩定性、高靈敏度、環境因素影響低、體積小和製作過程簡單等優點。本論文將藉由掃描式電子顯微鏡分析氧化鎳薄膜之表面微觀、元素組成及表面粗糙度。
在元件製程方面，首先，吾人利用熱蒸鍍法製作鉻/鉑的指叉式電極於藍寶石基板上，接著以射頻磁控濺鍍法製備氧化鎳感測薄膜，最後以快速熱退火增加氧化鎳的結晶性，並針對各種不同濃度的氣體進行氣體感測分析。
其次，吾人以不同催化金屬結合氧化鎳感測薄膜，改善金屬氧化物系感測器之選擇性問題。吾人以鈀和鉑金屬薄膜催化氫氣與氨氣，實驗結果，經過修飾後的氧化鎳薄膜分別顯示對氫氣與氨氣均有良好的感測能力。
最後，吾人將鈀奈米顆粒塗佈於鈀/氧化鎳薄膜結構上，藉由鈀粒子對氫氣的良好催化反應及粗造的比表面積，可增加氫氣吸附座，進而增加感測靈敏度與減少反應時間，使得氫氣感測性能大幅提升。

In the recent year, the environment disaster and human safety were followed in the development of technology. However, gas sensors also were widely applied in chemical industry, cultivation, fisher, food industry, and environment monitor, etc. Metal oxide-based gas sensor had advantages, such as chemical stability, highly sensitivity, environmental sustainability, small component, and easy fabrication. In this study, surface morphology, element compose and surface roughness of nickel oxide (NiO) membrane was analyzed by scanning electron microscopy (SEM).
First, the Cr/Pt interdigitated electrodes were fabricated on a sapphire substrate by thermal evaporation. Then, the NiO sensing layer was deposited by radio-frequency (RF) sputtering. Finally, the crystalline of NiO was improved by rapid thermal annealing (RTA) and gas sensing properties were discussed.
However, the normal nickel oxide gas sensor had bad selectivity on the different gas concentration. So that, we utilized different catalytic metal which could induce selectivity to composite NiO film. Then, palladium and platinum catalytic metal film by thermal evaporation could effectively catalytic hydrogen and ammonia gas. The result, both hydrogen and ammonia gas had excessive sensing property.
Finally, palladium nanoparticles were deposited on the palladium film/NiO sensing film structure. Palladium nanoparticles had great catalytic to hydrogen. Because of high surface to volume ratios could increase sensitivity and shorten detect time, improved hydrogen sensing property.

[1] K. Chikkadi, M. Muoth, W. Liu, V. Maiwald, and C. Hierold, "Enhanced signal-to-noise ratio in pristine, suspended carbon nanotube gas sensors," Sensors and Actuators B: Chemical, vol. 196, pp. 682-690, 2014.
[2] C.-T. Chang and K.-L. Lin, "Assessment of the strategies for reducing VOCs emission from polyurea-formaldehyde resin synthetic fiber leather industry in Taiwan," Resources, Conservation and Recycling, vol. 46, pp. 321-334, 2006.
[3] M. O. Ozbek and J. W. Niemantsverdriet, "Methane, formaldehyde and methanol formation pathways from carbon monoxide and hydrogen on the (0 0 1) surface of the iron carbide χ-Fe5C2," Journal of Catalysis, vol. 325, pp. 9-18, 2015.
[4] W. Liang, M. Lv, and X. Yang, "The effect of humidity on formaldehyde emission parameters of a medium-density fiberboard: Experimental observations and correlations," Building and Environment, vol. 101, pp. 110-115, 2016.
[5] S. Feng, Z. Yuan, M. Leitch, H. Shui, and C. C. Xu, "Effects of bark extraction before liquefaction and liquid oil fractionation after liquefaction on bark-based phenol formaldehyde resoles," Industrial Crops and Products, vol. 84, pp. 330-336, 2016.
[6] G. G. Allan, J. Dutkiewicz, and E. J. Gilmartin, "Long-term stability of urea-formaldehyde foam insulation," Environmental Science & Technology, vol. 14, pp. 1235-1240, 1980.
[7] C. Demirkir, S. Colak, and I. Aydin, "Some technological properties of wood–styrofoam composite panels," Composites Part B: Engineering, vol. 55, pp. 513-517, 2013.
[8] R. Goulding, "Book Reviews : Formaldehyde (Environmental Health Criteria 89). Published by WHO Geneva, 1989, 1989. Price Sw. fr. 22. Paperback. Pp 219. ISBN 92 4 154289 6," The Journal of the Royal Society for the Promotion of Health, vol. 111, p. 38, 1991.
[9] J. H. E. Arts, M. A. J. Rennen, and C. de Heer, "Inhaled formaldehyde: Evaluation of sensory irritation in relation to carcinogenicity," Regulatory Toxicology and Pharmacology, vol. 44, pp. 144-160, 2006.
[10] J. Suehiro, S.-I. Hidaka, S. Yamane, and K. Imasaka, "Fabrication of interfaces between carbon nanotubes and catalytic palladium using dielectrophoresis and its application to hydrogen gas sensor," Sensors and Actuators B: Chemical, vol. 127, pp. 505-511, 2007.
[11] C.-L. Hsu, K.-C. Chen, T.-Y. Tsai, and T.-J. Hsueh, "Fabrication of gas sensor based on p-type ZnO nanoparticles and n-type ZnO nanowires," Sensors and Actuators B: Chemical, vol. 182, pp. 190-196, 2013.
[12] S. Pati, P. Banerji, and S. B. Majumder, "n- to p- type carrier reversal in nanocrystalline indium doped ZnO thin film gas sensors," International Journal of Hydrogen Energy, vol. 39, pp. 15134-15141, 2014.
[13] A. Sutka, M. Stingaciu, G. Mezinskis, and A. Lusis, "An alternative method to modify the sensitivity of p-type NiFe2O4 gas sensor," Journal of Materials Science, vol. 47, pp. 2856-2863, 2012.
[14] J. Cao, Z. Wang, R. Wang, S. Liu, T. Fei, L. Wang, et al., "Synthesis of core-shell [small alpha]-Fe2O3@NiO nanofibers with hollow structures and their enhanced HCHO sensing properties," Journal of Materials Chemistry A, vol. 3, pp. 5635-5641, 2015.
[15] N. Yamazoe, K. Suematsu, and K. Shimanoe, "Surface chemistry of neat tin oxide sensor for response to hydrogen gas in air," Sensors and Actuators B: Chemical, vol. 227, pp. 403-410, 2016.
[16] R. Ab Kadir, Z. Li, A. Z. Sadek, R. Abdul Rani, A. S. Zoolfakar, M. R. Field, et al., "Electrospun Granular Hollow SnO2 Nanofibers Hydrogen Gas Sensors Operating at Low Temperatures," The Journal of Physical Chemistry C, vol. 118, pp. 3129-3139, 2014.
[17] A. D. Marcellis, G. Ferri, P. Mantenuto, L. Giancaterini, and C. Cantalini, "Hydrogen Resistive Gas Sensor and Its Wide-Range Current-Mode Electronic Read-Out Circuit," IEEE Sensors Journal, vol. 13, pp. 2792-2798, 2013.
[18] Y. H. Kahng, W. Lu, R. G. Tobin, R. Loloee, and R. N. Ghosh, "The role of oxygen in hydrogen sensing by a platinum-gate silicon carbide gas sensor: An ultrahigh vacuum study," Journal of Applied Physics, vol. 105, p. 064511, 2009.
[19] T.-Y. Chen, H.-I. Chen, C.-S. Hsu, C.-C. Huang, J.-S. Wu, P.-C. Chou, et al., "Characteristics of ZnO nanorods-based ammonia gas sensors with a cross-linked configuration," Sensors and Actuators B: Chemical, vol. 221, pp. 491-498, 2015.
[20] R. H. Vignesh, K. V. Sankar, S. Amaresh, Y. S. Lee, and R. K. Selvan, "Synthesis and characterization of MnFe2O4 nanoparticles for impedometric ammonia gas sensor," Sensors and Actuators B: Chemical, vol. 220, pp. 50-58, 2015.
[21] P. C. Chou, H. I. Chen, I. P. Liu, C. C. Chen, J. K. Liou, K. S. Hsu, et al., "On the Ammonia Gas Sensing Performance of a RF Sputtered NiO Thin-Film Sensor," IEEE Sensors Journal, vol. 15, pp. 3711-3715, 2015.
[22] P. X. Zhao, Y. Tang, J. Mao, Y. X. Chen, H. Song, J. W. Wang, et al., "One-Dimensional MoS2-Decorated TiO2 nanotube gas sensors for efficient alcohol sensing," Journal of Alloys and Compounds, vol. 674, pp. 252-258, 2016.
[23] A. Mirzaei, S. Park, G.-J. Sun, H. Kheel, and C. Lee, "CO gas sensing properties of In4Sn3O12 and TeO2 composite nanoparticle sensors," Journal of Hazardous Materials, vol. 305, pp. 130-138, 2016.
[24] C.-L. Hsu, J.-Y. Tsai, and T.-J. Hsueh, "Ethanol gas and humidity sensors of CuO/Cu2O composite nanowires based on a Cu through-silicon via approach," Sensors and Actuators B: Chemical, vol. 224, pp. 95-102, 2016.
[25] J. Liao, Z. Li, G. Wang, C. Chen, S. Lv, and M. Li, "ZnO nanorod/porous silicon nanowire hybrid structures as highly-sensitive NO2 gas sensors at room temperature," Physical Chemistry Chemical Physics, vol. 18, pp. 4835-4841, 2016.
[26] C. Balamurugan and D. W. Lee, "Perovskite hexagonal YMnO3 nanopowder as p-type semiconductor gas sensor for H2S detection," Sensors and Actuators B: Chemical, vol. 221, pp. 857-866, 2015.
[27] J. Qin, Z. Cui, X. Yang, S. Zhu, Z. Li, and Y. Liang, "Three-dimensionally ordered macroporous La1−xMgxFeO3 as high performance gas sensor to methanol," Journal of Alloys and Compounds, vol. 635, pp. 194-202, 2015.
[28] C. Balamurugan and D. W. Lee, "A selective NH3 gas sensor based on mesoporous p-type NiV2O6 semiconducting nanorods synthesized using solution method," Sensors and Actuators B: Chemical, vol. 192, pp. 414-422, 2014.
[29] A. Bejaoui, J. Guerin, J. A. Zapien, and K. Aguir, "Theoretical and experimental study of the response of CuO gas sensor under ozone," Sensors and Actuators B: Chemical, vol. 190, pp. 8-15, 2014.
[30] A. Bejaoui, J. Guerin, and K. Aguir, "Modeling of a p-type resistive gas sensor in the presence of a reducing gas," Sensors and Actuators B: Chemical, vol. 181, pp. 340-347, 2013.
[31] H. Yan, P. Song, S. Zhang, J. Zhang, Z. Yang, and Q. Wang, "A low temperature gas sensor based on Au-loaded MoS2 hierarchical nanostructures for detecting ammonia," Ceramics International, vol. 42, pp. 9327-9331, 2016.
[32] L. Wang, Z. Lou, R. Zhang, T. Zhou, J. Deng, and T. Zhang, "Hybrid Co3O4/SnO2 Core–Shell Nanospheres as Real-Time Rapid-Response Sensors for Ammonia Gas," ACS Applied Materials & Interfaces, vol. 8, pp. 6539-6545, 2016/03/16 2016.
[33] S.-K. Lee, D. Chang, and S. W. Kim, "Gas sensors based on carbon nanoflake/tin oxide composites for ammonia detection," Journal of Hazardous Materials, vol. 268, pp. 110-114, 2014.
[34] Y. Lin, W. Wei, Y. Li, F. Li, J. Zhou, D. Sun, et al., "Preparation of Pd nanoparticle-decorated hollow SnO2 nanofibers and their enhanced formaldehyde sensing properties," Journal of Alloys and Compounds, vol. 651, pp. 690-698, 2015.
[35] L. Xu, R. Xing, J. Song, W. Xu, and H. Song, "ZnO-SnO2 nanotubes surface engineered by Ag nanoparticles: synthesis, characterization, and highly enhanced HCHO gas sensing properties," Journal of Materials Chemistry C, vol. 1, pp. 2174-2182, 2013.
[36] L. Han, D. Wang, Y. Lu, T. Jiang, B. Liu, and Y. Lin, "Visible-Light-Assisted HCHO Gas Sensing Based on Fe-Doped Flowerlike ZnO at Room Temperature," The Journal of Physical Chemistry C, vol. 115, pp. 22939-22944, 2011.
[37] P. V. Tong, N. D. Hoa, N. V. Duy, V. V. Quang, N. T. Lam, and N. V. Hieu, "In-situ decoration of Pd nanocrystals on crystalline mesoporous NiO nanosheets for effective hydrogen gas sensors," International Journal of Hydrogen Energy, vol. 38, pp. 12090-12100, 2013.
[38] J. Wang, L. Wei, L. Zhang, C. Jiang, E. Siu-Wai Kong, and Y. Zhang, "Preparation of high aspect ratio nickel oxide nanowires and their gas sensing devices with fast response and high sensitivity," Journal of Materials Chemistry, vol. 22, pp. 8327-8335, 2012.
[39] T. Hübert, L. Boon-Brett, G. Black, and U. Banach, "Hydrogen sensors – A review," Sensors and Actuators B: Chemical, vol. 157, pp. 329-352, 2011.
[40] W. Small Iv, D. J. Maitland, T. S. Wilson, J. P. Bearinger, S. A. Letts, and J. E. Trebes, "Development of a prototype optical hydrogen gas sensor using a getter-doped polymer transducer for monitoring cumulative exposure: Preliminary results," Sensors and Actuators B: Chemical, vol. 139, pp. 375-379, 2009.
[41] W. Shin, M. Matsumiya, F. Qiu, N. Izu, and N. Murayama, "Thermoelectric gas sensor for detection of high hydrogen concentration," Sensors and Actuators B: Chemical, vol. 97, pp. 344-347, 2004.
[42] Y.-Y. Lv, J. Wu, and Z.-K. Xu, "Colorimetric and fluorescent sensor constructing from the nanofibrous membrane of porphyrinated polyimide for the detection of hydrogen chloride gas," Sensors and Actuators B: Chemical, vol. 148, pp. 233-239, 2010.
[43] S. F. Bamsaoud, S. B. Rane, R. N. Karekar, and R. C. Aiyer, "Nano particulate SnO2 based resistive films as a hydrogen and acetone vapour sensor," Sensors and Actuators B: Chemical, vol. 153, pp. 382-391, 2011.
[44] C. Lu and Z. Chen, "High-temperature resistive hydrogen sensor based on thin nanoporous rutile TiO2 film on anodic aluminum oxide," Sensors and Actuators B: Chemical, vol. 140, pp. 109-115, 2009.
[45] R. K. Dixon, J. Li, and M. Q. Wang, "13 - Progress in hydrogen energy infrastructure development—addressing technical and institutional barriers A2 - Gupta, Ram B," in Compendium of Hydrogen Energy, A. Basile and T. N. Veziroğlu, Eds., ed: Woodhead Publishing, pp. 323-343,2016
[46] R. K. Malhotra, L. M. Das, A. Sharma, D. K. Tuli, and S. Sachdeva, "Preface to the special issue section on “Moving towards hydrogen economy in India: Challenges and opportunities in production, storage and usage of hydrogen energy”," International Journal of Hydrogen Energy, vol. 41, p. 6084, 2016.
[47] R. Á. Fernández, F. B. Cilleruelo, and I. V. Martínez, "A new approach to battery powered electric vehicles: A hydrogen fuel-cell-based range extender system," International Journal of Hydrogen Energy, vol. 41, pp. 4808-4819, 2016.
[48] C.-H. Han, S.-D. Han, and I. Singh, "Thermoelectric hydrogen sensor using Li x Ni1-x O synthesized by molten salt method," Korean Journal of Chemical Engineering, vol. 23, pp. 362-366, 2006.
[49] X. Liu, N. Chen, B. Han, X. Xiao, G. Chen, I. Djerdj, et al., "Nanoparticle cluster gas sensor: Pt activated SnO2 nanoparticles for NH3 detection with ultrahigh sensitivity," Nanoscale, vol. 7, pp. 14872-14880, 2015.
[50] T. Usagawa and Y. Kikuchi, "Device characteristics for Pt–Ti–O gate Si–MISFETs hydrogen gas sensors," Sensors and Actuators B: Chemical, vol. 160, pp. 105-114, 2011.
[51] A. Z. Sadek, S. Choopun, W. Wlodarski, S. J. Ippolito, and K. Kalantar-zadeh, "Characterization of ZnO Nanobelt-Based Gas Sensor for H, NO, and Hydrocarbon Sensing," IEEE Sensors Journal, vol. 7, pp. 919-924, 2007.
[52] J. Dhakshinamoorthy and B. Pullithadathil, "New Insights Towards Electron Transport Mechanism of Highly Efficient p-Type CuO (111) Nanocuboids-Based H2S Gas Sensor," The Journal of Physical Chemistry C, vol. 120, pp. 4087-4096, 2016.
[53] Z. D. Lin, S. J. Young, and S. J. Chang, "Carbon Nanotube Thin Films Functionalized via Loading of Au Nanoclusters for Flexible Gas Sensors Devices," IEEE Transactions on Electron Devices, vol. 63, pp. 476-480, 2016.
[54] A. Sharma, M. Tomar, and V. Gupta, "A low temperature operated NO2 gas sensor based on TeO2/SnO2 p–n heterointerface," Sensors and Actuators B: Chemical, vol. 176, pp. 875-883, 2013.
[55] J. X. Wang, X. W. Sun, H. Huang, Y. C. Lee, O. K. Tan, M. B. Yu, et al., "A two-step hydrothermally grown ZnO microtube array for CO gas sensing," Applied Physics A, vol. 88, pp. 611-615, 2007.
[56] R. W. J. Scott, S. M. Yang, G. Chabanis, N. Coombs, D. E. Williams, and G. A. Ozin, "Tin Dioxide Opals and Inverted Opals: Near-Ideal Microstructures for Gas Sensors," Advanced Materials, vol. 13, pp. 1468-1472, 2001.
[57] J. Cui, L. Shi, T. Xie, D. Wang, and Y. Lin, "UV-light illumination room temperature HCHO gas-sensing mechanism of ZnO with different nanostructures," Sensors and Actuators B: Chemical, vol. 227, pp. 220-226, 2016.
[58] R. Bouchet, E. Siebert, and G. Vitter, "Polybenzimidazole‐Based Hydrogen Sensors I. Mechanism of Response with an E-TEK Gas Diffusion Electrode," Journal of The Electrochemical Society, vol. 147, pp. 3125-3130, 2000.
[59] J. Guo, J. Zhang, H. Gong, D. Ju, and B. Cao, "Au nanoparticle-functionalized 3D SnO2 microstructures for high performance gas sensor," Sensors and Actuators B: Chemical, vol. 226, pp. 266-272, 2016.
[60] M. Matsumiya, F. Qiu, W. Shin, N. Izu, I. Matsubara, N. Murayama, et al., "Thermoelectric CO Gas Sensor Using Thin-Film Catalyst of Au and Co3 O 4," Journal of The Electrochemical Society, vol. 151, pp. H7-H10, 2004.
[61] J. Moon, H.-P. Hedman, M. Kemell, A. Tuominen, and R. Punkkinen, "Hydrogen sensor of Pd-decorated tubular TiO2 layer prepared by anodization with patterned electrodes on SiO2/Si substrate," Sensors and Actuators B: Chemical, vol. 222, pp. 190-197, 2016.
[62] A. Keffous, A. Cheriet, T. Hadjersi, Y. Boukennous, N. Gabouze, A. Boukezzata, et al., "40 Å Platinum–porous SiC gas sensor: Investigation sensing properties of H2 gas," Physica B: Condensed Matter, vol. 408, pp. 193-197, 2013.
[63] D. Ghosh, B. Ghosh, S. Hussain, S. Chaudhuri, R. Bhar, and A. K. Pal, "Novel BN/Pd composite films for stable liquid petroleum gas sensor," Applied Surface Science, vol. 263, pp. 788-794, 2012.
[64] M. Urbańczyk, E. Maciak, K. Gut, T. Pustelny, and W. Jakubik, "Layered thin film nanostructures of Pd/WO3-x as resistance gas sensors," in Bulletin of the Polish Academy of Sciences: Technical Sciences vol. 59, ed, p. 401, 2011.
[65] N. Q. Lich, T. P. Thanh, D. V. Truong, P. T. Kien, N. C. Tu, L. H. Bac, et al., "Pt- and Ag-Decorated Carbon Nanotube Network Layers for Enhanced NH Gas Sensitivity at Room Temperature," MATERIALS TRANSACTIONS, vol. 56, pp. 1399-1402, 2015.
[66] M. Horprathum, T. Srichaiyaperk, B. Samransuksamer, A. Wisitsoraat, P. Eiamchai, S. Limwichean, et al., "Ultrasensitive Hydrogen Sensor Based on Pt-Decorated WO3 Nanorods Prepared by Glancing-Angle dc Magnetron Sputtering," ACS Applied Materials & Interfaces, vol. 6, pp. 22051-22060, 2014.
[67] J. Fu, C. Zhao, J. Zhang, Y. Peng, and E. Xie, "Enhanced Gas Sensing Performance of Electrospun Pt-Functionalized NiO Nanotubes with Chemical and Electronic Sensitization," ACS Applied Materials & Interfaces, vol. 5, pp. 7410-7416, 2013.
[68] S. Joo, I. Muto, and N. Hara, "Hydrogen Gas Sensor Using Pt- and Pd-Added Anodic TiO2 Nanotube Films," Journal of The Electrochemical Society, vol. 157, pp. J221-J226, 2010.
[69] M. Matsumiya, W. Shin, N. Izu, and N. Murayama, "Nano-structured thin-film Pt catalyst for thermoelectric hydrogen gas sensor," Sensors and Actuators B: Chemical, vol. 93, pp. 309-315, 2003.
[70] M. Gaidi, J. L. Hazemann, I. Matko, B. Chenevier, M. Rumyantseva, A. Gaskov, et al., "Role of Pt Aggregates in Pt / SnO2 Thin Films Used as Gas Sensors Investigations of the Catalytic Effect," Journal of The Electrochemical Society, vol. 147, pp. 3131-3138, 2000.
[71] M. de la L. Olvera and R. Asomoza, "SnO2 and SnO2:Pt thin films used as gas sensors," Sensors and Actuators B: Chemical, vol. 45, pp. 49-53, 1997.
[72] S. V. Patel, K. D. Wise, J. L. Gland, M. Zanini-Fisher, and J. W. Schwank, "Characteristics of silicon-micromachined gas sensors based on Pt/TiOx thin films," Sensors and Actuators B: Chemical, vol. 42, pp. 205-215, 1997.
[73] I.-S. Hwang, J.-K. Choi, H.-S. Woo, S.-J. Kim, S.-Y. Jung, T.-Y. Seong, et al., "Facile Control of C2H5OH Sensing Characteristics by Decorating Discrete Ag Nanoclusters on SnO2 Nanowire Networks," ACS Applied Materials & Interfaces, vol. 3, pp. 3140-3145, 2011.
[74] A. Kolmakov, D. O. Klenov, Y. Lilach, S. Stemmer, and M. Moskovits, "Enhanced Gas Sensing by Individual SnO2 Nanowires and Nanobelts Functionalized with Pd Catalyst Particles," Nano Letters, vol. 5, pp. 667-673, 2005.
[75] R. K. Joshi, Q. Hu, F. Alvi, N. Joshi, and A. Kumar, "Au Decorated Zinc Oxide Nanowires for CO Sensing," The Journal of Physical Chemistry C, vol. 113, pp. 16199-16202, 2009.
[76] S. Mukherjee, B. Ramalingam, and S. Gangopadhyay, "Hydrogen spillover at sub-2 nm Pt nanoparticles by electrochemical hydrogen loading," Journal of Materials Chemistry A, vol. 2, pp. 3954-3960, 2014.
[77] G. M. Psofogiannakis and G. E. Froudakis, "Fundamental studies and perceptions on the spillover mechanism for hydrogen storage," Chemical Communications, vol. 47, pp. 7933-7943, 2011.
[78] D. A. Dowden, "The spillover of chemisorbed species," in Catalysis: Volume 3. vol. 3, C. Kemball and D. A. Dowden, Eds., ed: The Royal Society of Chemistry, 1980, pp. 136-168.
[79] C. Liu, Q. Kuang, Z. Xie, and L. Zheng, "The effect of noble metal (Au, Pd and Pt) nanoparticles on the gas sensing performance of SnO2-based sensors: a case study on the {221} high-index faceted SnO2 octahedra," CrystEngComm, vol. 17, pp. 6308-6313, 2015.
[80] B. Chen, C. Liu, L. Ge, and K. Hayashi, "Localized surface plasmon resonance gas sensor of Au nano-islands coated with molecularly imprinted polymer: Influence of polymer thickness on sensitivity and selectivity," Sensors and Actuators B: Chemical, vol. 231, pp. 787-792, 2016.
[81] X. Liu, J. Zhang, L. Wang, T. Yang, X. Guo, S. Wu, et al., "3D hierarchically porous ZnO structures and their functionalization by Au nanoparticles for gas sensors," Journal of Materials Chemistry, vol. 21, pp. 349-356, 2011.
[82] B. Liu, D. Cai, Y. Liu, H. Li, C. Weng, G. Zeng, et al., "High-performance room-temperature hydrogen sensors based on combined effects of Pd decoration and Schottky barriers," Nanoscale, vol. 5, pp. 2505-2510, 2013.
[83] H.-Y. Lai and C.-H. Chen, "Highly sensitive room-temperature CO gas sensors: Pt and Pd nanoparticle-decorated In2O3 flower-like nanobundles," Journal of Materials Chemistry, vol. 22, pp. 13204-13208, 2012.
[84] R. K. Joshi and F. E. Kruis, "Influence of Ag particle size on ethanol sensing of SnO1.8:Ag nanoparticle films: A method to develop parts per billion level gas sensors," Applied Physics Letters, vol. 89, p. 153116, 2006.
[85] Y. Zhang, Z. Zheng, and F. Yang, "Highly Sensitive and Selective Alcohol Sensors based on Ag-Doped In2O3 Coating," Industrial & Engineering Chemistry Research, vol. 49, pp. 3539-3543, 2010.
[86] G. Zhu, Y. Liu, H. Xu, Y. Chen, X. Shen, and Z. Xu, "Photochemical deposition of Ag nanocrystals on hierarchical ZnO microspheres and their enhanced gas-sensing properties," CrystEngComm, vol. 14, pp. 719-725, 2012.
[87] X. Cheng, Y. Xu, S. Gao, H. Zhao, and L. Huo, "Ag nanoparticles modified TiO2 spherical heterostructures with enhanced gas-sensing performance," Sensors and Actuators B: Chemical, vol. 155, pp. 716-721, 2011.
[88] I. Sta, M. Jlassi, M. Kandyla, M. Hajji, P. Koralli, F. Krout, et al., "Surface functionalization of sol–gel grown NiO thin films with palladium nanoparticles for hydrogen sensing," International Journal of Hydrogen Energy, vol. 41, pp. 3291-3298, 2016.
[89] B. Wang, Z. Q. Zheng, L. F. Zhu, Y. H. Yang, and H. Y. Wu, "Self-assembled and Pd decorated Zn2SnO4/ZnO wire-sheet shape nano-heterostructures networks hydrogen gas sensors," Sensors and Actuators B: Chemical, vol. 195, pp. 549-561, 2014.
[90] A. Esfandiar, S. Ghasemi, A. Irajizad, O. Akhavan, and M. R. Gholami, "The decoration of TiO2/reduced graphene oxide by Pd and Pt nanoparticles for hydrogen gas sensing," International Journal of Hydrogen Energy, vol. 37, pp. 15423-15432, 2012.
[91] E. Ghadiri, A. Iraji zad, and F. Razi, "Hydrogen Sensing Properties of Pure and Pd Activated WO3 Nanostructured Films," Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, vol. 37, pp. 453-456, 2007.
[92] J. Wang, P. Zhang, J.-Q. Qi, and P.-J. Yao, "Silicon-based micro-gas sensors for detecting formaldehyde," Sensors and Actuators B: Chemical, vol. 136, pp. 399-404, 2009.
[93] Y. Zheng, J. Wang, and P. Yao, "Formaldehyde sensing properties of electrospun NiO-doped SnO2 nanofibers," Sensors and Actuators B: Chemical, vol. 156, pp. 723-730, 2011.
[94] I. Castro-Hurtado, J. Herrán, G. G. Mandayo, and E. Castaño, "Studies of influence of structural properties and thickness of NiO thin films on formaldehyde detection," Thin Solid Films, vol. 520, pp. 947-952, 2011.
[95] C. W. Na, H.-S. Woo, and J.-H. Lee, "Design of highly sensitive volatile organic compound sensors by controlling NiO loading on ZnO nanowire networks," RSC Advances, vol. 2, pp. 414-417, 2012.
[96] X. Gou, G. Wang, J. Yang, J. Park, and D. Wexler, "Chemical synthesis, characterisation and gas sensing performance of copper oxide nanoribbons," Journal of Materials Chemistry, vol. 18, pp. 965-969, 2008.