本研究成功使用五氧化二釩 (V2O5) 研製出高選擇性、高穩定度、有可逆性的氣體感測器。使用C-plane型藍寶石作為元件基底，蒸鍍製作鉻鉑電極並且濺鍍五氧化二釩薄膜當作感測層。利用快速蒸鍍法在元件表面製作奈米金屬粒子藉此提升元件的感測特性、感測區域之比表面積、催化活性、粗糙度、感測倍率。
為了證明元件表面確實存在奈米金屬粒子，透過掃描電子顯微鏡 (SEM)、穿透式電子顯微鏡 (TEM)、能量色散X-射線光譜 (EDS)、原子力顯微鏡 (AFM)、比表面積與孔隙度分析儀 (BET) 和X光繞射分析 (XRD) 的分析結果證明了奈米金屬粒子和五氧化二釩薄膜確實存在。

In this study, vanadium pentoxide (V2O5) was used to develop a gas sensor with high selectivity, high stability, and reversibility. Use a C-plane type sapphire as the element substrate, to prepare chromium-platinum electrode by vapor deposition, and sputtering. Next, employ rapid vapor deposition to produce nano-metal particle protrusions on the surface of the element for improving the sensing characteristics of the element, the alignment ratio of the sensing area, and catalysis activity, volume, sensing magnification.
In order to examine that nano-metal particles are indeed present on the surface of the device, many studies. Such as a scanning electron microscope (SEM), transmission electron microscope (TEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscope (AFM), the ratio scale and verticality analyzer (BET) and X-ray diffraction analysis (XRD) analysis were employed. Results identify results prove that nano-metal particles and vanadium pentoxide thin film are existed exactly.

[1] T.-Y. Chen, H.-I. Chen, C.-S. Hsu, C.-C. Huang, J.-S. Wu, P.-C. Chou, and W.-C. Liu, "Characteristics of ZnO nanorods-based ammonia gas sensors with a cross-linked configuration," Sens. Actuators B, Chem., vol. 221, pp. 491-498, 2015.
[2] V. Talwar, O. Singh, and R.C. Singh, "ZnO assisted polyaniline nanofibers and its application as ammonia gas sensor," Sens. Actuators B, Chem., vol. 191, pp. 276-282, 2014.
[3] Y. Izumi, "Recent advances in the photocatalytic conversion of carbon dioxide to fuels with water and/or hydrogen using solar energy and beyond," Coordination Chemistry Reviews, vol. 257, pp. 171-186, 2013.
[4] N.H. Al-Hardan, M.J. Abdullah, and A.A. Aziz, "Sensing mechanism of hydrogen gas sensor based on RF-sputtered ZnO thin films," International Journal of Hydrogen Energy, vol. 35, pp. 4428-4434, 2010.
[5] V.B. Raj, A.T. Nimal, Y. Parmar, M.U. Sharma, K. Sreenivas, and V. Gupta, "Cross-sensitivity and selectivity studies on ZnO surface acoustic wave ammonia sensor," Sens. Actuators B, Chem., vol. 147, pp. 517-524, 2010.
[6] C. Xie, L. Xiao, M. Hu, Z. Bai, X. Xia, and D. Zeng, "Fabrication and formaldehyde gas-sensing property of ZnO–MnO2 coplanar gas sensor arrays," Sens. Actuators B, Chem., vol. 145, pp. 457-463, 2010.
[7] R. Lontio Fomekong, H.M. Tedjieukeng Kamta, J. Ngolui Lambi, D. Lahem, P. Eloy, M. Debliquy, and A. Delcorte, "A sub-ppm level formaldehyde gas sensor based on Zn-doped NiO prepared by a co-precipitation route," J. Alloys Compd., vol. 731, pp. 1188-1196, 2018.
[8] J. Xu, X. Jia, X. Lou, G. Xi, J. Han, and Q. Gao, "Selective detection of HCHO gas using mixed oxides of ZnO/ZnSnO3," Sens. Actuators B, Chem., vol. 120, pp. 694-699, 2007.
[9] O. Lupan, G. Chai, and L. Chow, "Novel hydrogen gas sensor based on single ZnO nanorod," Microelectron. Eng., vol. 85, pp. 2220-2225, 2008.
[10] A.Z. Sadek, W. Wlodarski, Y.X. Li, W. Yu, X. Li, X. Yu, and K. Kalantar-zadeh, "A ZnO nanorod based layered ZnO/64° YX LiNbO3 SAW hydrogen gas sensor," Thin Solid Films, vol. 515, pp. 8705-8708, 2007.
[11] J.J. Hassan, M.A. Mahdi, C.W. Chin, H. Abu-Hassan, and Z. Hassan, "A high-sensitivity room-temperature hydrogen gas sensor based on oblique and vertical ZnO nanorod arrays," Sens. Actuators B, Chem., vol. 176, pp. 360-367, 2013.
[12] A.Z. Sadek, W. Wlodarski, K. Shin, R.B. Kaner, and K. Kalantar-zadeh, "A polyaniline/WO3 nanofiber composite-based ZnO/64° YX LiNbO3 SAW hydrogen gas sensor," Synth. Met., vol. 158, pp. 29-32, 2008.
[13] Y.T. Lim, J.Y. Son, and J.S. Rhee, "Vertical ZnO nanorod array as an effective hydrogen gas sensor," Ceram. Int., vol. 39, pp. 887-890, 2013.
[14] J.J. Hassan, M.A. Mahdi, C.W. Chin, H. Abu-Hassan, and Z. Hassan, "Room temperature hydrogen gas sensor based on ZnO nanorod arrays grown on a SiO2/Si substrate via a microwave-assisted chemical solution method," J. Alloys Compd., vol. 546, pp. 107-111, 2013.
[15] K. Anand, O. Singh, M.P. Singh, J. Kaur, and R.C. Singh, "Hydrogen sensor based on graphene/ZnO nanocomposite," Sens. Actuators B, Chem., vol. 195, pp. 409-415, 2014.
[16] M. Aslam, V.A. Chaudhary, I.S. Mulla, S.R. Sainkar, A.B. Mandale, A.A. Belhekar, and K. Vijayamohanan, "A highly selective ammonia gas sensor using surface-ruthenated zinc oxide," Sensors and Actuators A: Physical, vol. 75, pp. 162-167, 1999.
[17] 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.
[18] R. Wang, S. Yang, R. Deng, W. Chen, H. Zhang, Y. Liu, and G. Zakharova, "Enhanced gas sensing properties of V2O5 nanowires decorated with SnO2 nanoparticles to ethanol at room temperature," RSC Adv., vol. 5, pp., 2015.
[19] Y. Zheng, J. Wang, and P. Yao, "Formaldehyde sensing properties of electrospun NiO-doped SnO2 nanofibers," Sens. Actuators B, Chem., vol. 156, pp. 723-730, 2011.
[20] S. Tian, X. Ding, D. Zeng, J. Wu, S. Zhang, and C. Xie, "A low temperature gas sensor based on Pd-functionalized mesoporous SnO2 fibers for detecting trace formaldehyde," RSC Advances, vol. 3, pp. 11823-11831, 2013.
[21] C.-H. Han, S.-D. Han, I. Singh, and T. Toupance, "Micro-bead of nano-crystalline F-doped SnO2 as a sensitive hydrogen gas sensor," Sens. Actuators B, Chem., vol. 109, pp. 264-269, 2005.
[22] A. Katsuki, and K. Fukui, "H2 selective gas sensor based on SnO2," Sens. Actuators B, Chem., vol. 52, pp. 30-37, 1998.
[23] V.V. Petrov, T.N. Nazarova, A.N. Korolev, and N.F. Kopilova, "Thin sol–gel SiO2–SnOX–AgOy films for low temperature ammonia gas sensor," Sens. Actuators B, Chem., vol. 133, pp. 291-295, 2008.
[24] S.G. Pawar, M.A. Chougule, S.L. Patil, B.T. Raut, P.R. Godse, S. Sen, and V.B. Patil, "Room temperature ammonia gas sensor based on polyaniline-TiO2 nanocomposite," IEEE Sensors Journal, vol. 11, pp. 3417-3423, 2011.
[25] S. Lin, D. Li, J. Wu, X. Li, and S.A. Akbar, "A selective room temperature formaldehyde gas sensor using TiO2 nanotube arrays," Sens. Actuators B, Chem., vol. 156, pp. 505-509, 2011.
[26] M. Epifani, E. Comini, R. Díaz, C. Force, P. Siciliano, and G. Faglia, "TiO2 colloidal nanocrystals surface modification by V2O5 species: Investigation by 47,49Ti MAS-NMR and H2, CO and NO2 sensing properties," Applied Surface Science, vol. 351, pp. 1169-1173, 2015.
[27] J. Lee, D.H. Kim, S.-H. Hong, and J.Y. Jho, "A hydrogen gas sensor employing vertically aligned TiO2 nanotube arrays prepared by template-assisted method," Sens. Actuators B, Chem., vol. 160, pp. 1494-1498, 2011.
[28] H. Fu, X. Yang, X. An, W. Fan, X. Jiang, and A. Yu, "Experimental and theoretical studies of V2O5@TiO2 core-shell hybrid composites with high gas sensing performance towards ammonia," Sens. Actuators B, Chem., vol. 252, pp. 103-115, 2017.
[29] D. Schönauer-Kamin, M. Fleischer, and R. Moos, "Half-cell potential analysis of an ammonia sensor with the electrochemical cell Au | YSZ | Au, V2O5-WO3-TiO2," Sensors, vol. 13, pp., 2013.
[30] P. Chou, H. Chen, I. Liu, C. Chen, J. Liou, K. Hsu, and W. Liu, "On the ammonia gas sensing performance of a rf sputtered NiO thin-film sensor," IEEE Sensors Journal, vol. 15, pp. 3711-3715, 2015.
[31] H.-I. Chen, C.-Y. Hsiao, W.-C. Chen, C.-H. Chang, T.-C. Chou, I.P. Liu, K.-W. Lin, and W.-C. Liu, "Characteristics of a Pt/NiO thin film-based ammonia gas sensor," Sens. Actuators B, Chem., vol. 256, pp. 962-967, 2018.
[32] J.A. Dirksen, K. Duval, and T.A. Ring, "NiO thin-film formaldehyde gas sensor," Sens. Actuators B, Chem., vol. 80, pp. 106-115, 2001.
[33] C.-Y. Lee, C.-M. Chiang, Y.-H. Wang, and R.-H. Ma, "A self-heating gas sensor with integrated NiO thin-film for formaldehyde detection," Sens. Actuators B, Chem., vol. 122, pp. 503-510, 2007.
[34] M. Matsumiya, W. Shin, N. Izu, and N. Murayama, "Nano-structured thin-film Pt catalyst for thermoelectric hydrogen gas sensor," Sens. Actuators B, Chem., vol. 93, pp. 309-315, 2003.
[35] M. Matsumiya, F. Qiu, W. Shin, N. Izu, N. Murayama, and S. Kanzaki, "Thin-film Li-doped NiO for thermoelectric hydrogen gas sensor," Thin Solid Films, vol. 419, pp. 213-217, 2002.
[36] X. Wang, N. Miura, and N. Yamazoe, "Study of WO3-based sensing materials for NH3 and NO detection," Sens. Actuators B, Chem., vol. 66, pp. 74-76, 2000.
[37] T. Chou, C. Chang, C. Lee, and W. Liu, "Ammonia sensing characteristics of a tungsten trioxide thin-film-based sensor," IEEE Trans. Electron Devices, vol. 66, pp. 696-701, 2019.
[38] I.P. Liu, C.-H. Chang, T.C. Chou, and K.-W. Lin, "Ammonia sensing performance of a platinum nanoparticle-decorated tungsten trioxide gas sensor," Sens. Actuators B, Chem., vol. 291, pp. 148-154, 2019.
[39] M. Penza, C. Martucci, and G. Cassano, "NOx gas sensing characteristics of WO3 thin films activated by noble metals (Pd, Pt, Au) layers," Sens. Actuators B, Chem., vol. 50, pp. 52-59, 1998.
[40] D.D. Nguyen, D.V. Dang, and D.C. Nguyen, "Hydrothermal synthesis and NH3 gas sensing property of WO3 nanorods at low temperature," Adv. Nat. Sci NanoSci., vol. 6, pp. 035006, 2015.
[41] Z. Li, Z. Hu, J. Peng, C. Wu, Y. Yang, F. Feng, P. Gao, J. Yang, and Y. Xie, "Ultrahigh infrared photoresponse from core-shell single-domain-VO2/V2O5 heterostructure in nanobeam," Adv. Funct. Mater., vol. 24, pp. 1821-1830, 2014.
[42] Y. Qin, G. Fan, K. Liu, and M. Hu, "Vanadium pentoxide hierarchical structure networks for high performance ethanol gas sensor with dual working temperature characteristic," Sens. Actuators B, Chem., vol. 190, pp. 141-148, 2014.
[43] A. Dhayal Raj, T. Pazhanivel, P. Suresh Kumar, D. Mangalaraj, D. Nataraj, and N. Ponpandian, "Self assembled V2O5 nanorods for gas sensors," Current Applied Physics, vol. 10, pp. 531-537, 2010.
[44] X. Yang, H. Xie, H. Fu, X. An, X. Jiang, and A. Yu, "Synthesis of hierarchical nanosheet-assembled V2O5 microflowers with high sensing properties towards amine," RSC Adv., vol. 6, pp., 2016.
[45] V. Modafferi, S. Trocino, A. Donato, G. Panzera, and G. Neri, "Electrospun V2O5 composite fibers: Synthesis, characterization and ammonia sensing properties," Thin Solid Films, vol. 548, pp. 689-694, 2013.
[46] V. Modafferi, G. Panzera, A. Donato, P.L. Antonucci, C. Cannilla, N. Donato, D. Spadaro, and G. Neri, "Highly sensitive ammonia resistive sensor based on electrospun V2O5 fibers," Sens. Actuators B, Chem., vol. 163, pp. 61-68, 2012.
[47] A.H. Shah, Y. Liu, G. Zakharova, and W. Chen, "Synthesis of vanadium pentoxide nanoneedles by physical vapour deposition and their high sensitive behavior towards acetone at room temperature," RSC Adv., vol. 5, pp., 2015.
[48] H. Yin, C. Song, Z. Wang, H. Shao, Y. Li, H. Deng, Q. Ma, and K. Yu, "Self-assembled vanadium oxide nanoflakes for p-type ammonia sensors at room temperature," Nanomaterials (Basel), vol. 9, pp. 317, 2019.
[49] M. Yu, X. Liu, Y. Wang, Y. Zheng, J. Zhang, M. Li, W. Lan, and Q. Su, "Gas sensing properties of p-type semiconducting vanadium oxide nanotubes," Applied Surface Science, vol. 258, pp. 9554-9558, 2012.
[50] G.P. Evans, M.J. Powell, I.D. Johnson, D.P. Howard, D. Bauer, J.A. Darr, and I.P. Parkin, "Room temperature vanadium dioxide–carbon nanotube gas sensors made via continuous hydrothermal flow synthesis," Sens. Actuators B, Chem., vol. 255, pp. 1119-1129, 2018.
[51] D.W. Bullett, "The energy band structure of V2O5: a simpler theoretical approach," Journal of Physics C: Solid State Physics, vol. 13, pp. L595-L599, 1980.
[52] M. Sathiya, A.S. Prakash, K. Ramesha, J.M. Tarascon, and A.K. Shukla, "V2O5-anchored carbon nanotubes for enhanced electrochemical energy storage," Journal of the American Chemical Society, vol. 133, pp. 16291-16299, 2011.
[53] E. Llobet, G. Molas, P. Molinàs, J. Calderer, X. Vilanova, J. Brezmes, J. Sueiras, and X. Correig, "Fabrication of highly selective tungsten oxide ammonia sensors," Journal of The Electrochemical Society, vol. 147, pp. 776-779, 2000.
[54] A. Sanger, A. Kumar, A. Kumar, J. Jaiswal, and R. Chandra, "A fast response/recovery of hydrophobic Pd/V2O5 thin films for hydrogen gas sensing," Sens. Actuators B, Chem., vol. 236, pp. 16-26, 2016.
[55] M. Amarnath, A. Heiner, and K. Gurunathan, "Surface bound nanostructures of ternary r-GO / Mn3O4/V2O5 system for room temperature selectivity of hydrogen gas," Ceram. Int., vol. 46, pp. 7336-7345, 2020.
[56] D.E. Williams, "Semiconducting oxides as gas-sensitive resistors," Sens. Actuators B, Chem., vol. 57, pp. 1-16, 1999.
[57] T. Chen, Q.J. Liu, Z.L. Zhou, and Y.D. Wang, "The fabrication and gas-sensing characteristics of the formaldehyde gas sensors with high sensitivity," Sens. Actuators B, Chem., vol. 131, pp. 301-305, 2008.
[58] W. Shin, M. Matsumiya, F. Qiu, N. Izu, and N. Murayama, "Thermoelectric gas sensor for detection of high hydrogen concentration," Sens. Actuators B, Chem., vol. 97, pp. 344-347, 2004.
[59] Y. Li, S.H. Chan, and Q. Sun, "Heterogeneous catalytic conversion of CO2: a comprehensive theoretical review," Nanoscale, vol. 7, pp. 8663-8683, 2015.
[60] W. Shin, M. Matsumiya, N. Izu, and N. Murayama, "Hydrogen-selective thermoelectric gas sensor," Sens. Actuators B, Chem., vol. 93, pp. 304-308, 2003.
[61] A. Kaniyoor, I. Jafri, T. Arockiadoss, and R. Sundara, "Nanostructured Pt decorated graphene and multi walled carbon nanotube based room temperature hydrogen gas sensor," Nanoscale, vol. 1, pp. 382-386, 2009.
[62] S. Sumida, S. Okazaki, S. Asakura, H. Nakagawa, H. Murayama, and T. Hasegawa, "Distributed hydrogen determination with fiber-optic sensor," Sens. Actuators B, Chem., vol. 108, pp. 508-514, 2005.
[63] K. Kyun Tae, S. Jun, and C. Sung Min, "Hydrogen gas sensor using Pd nanowires electro-deposited into anodized alumina template," IEEE Sensors Journal, vol. 6, pp. 509-513, 2006.
[64] A.Z. Adamyan, Z.N. Adamyan, V.M. Aroutiounian, A.H. Arakelyan, K.J. Touryan, and J.A. Turner, "Sol–gel derived thin-film semiconductor hydrogen gas sensor," International Journal of Hydrogen Energy, vol. 32, pp. 4101-4108, 2007.
[65] C.-H. Han, D.-W. Hong, I.-J. Kim, J. Gwak, S.-D. Han, and K.C. Singh, "Synthesis of Pd or Pt/titanate nanotube and its application to catalytic type hydrogen gas sensor," Sens. Actuators B, Chem., vol. 128, pp. 320-325, 2007.
[66] A. Šutka, M. Stingaciu, and G. Mezinskis, "An alternative method to modify the sensitivity of p-type NiFe2O4 gas sensor," Journal of Materials Science, vol. 47, pp. 2856–2863, 2011.
[67] J.W. Byon, M.-B. Kim, M.H. Kim, S.Y. Kim, S.H. Lee, B.C. Lee, and J.M. Baik, "Electrothermally induced highly responsive and highly selective vanadium oxide hydrogen sensor based on metal–insulator transition," The Journal of Physical Chemistry C, vol. 116, pp. 226-230, 2012.
[68] Y.-T. Wang, W.-T. Whang, and C.-H. Chen, "Hollow V2O5 nanoassemblies for high-performance room-temperature hydrogen sensors," ACS Applied Materials & Interfaces, vol. 7, pp. 8480-8487, 2015.
[69] C. Imawan, H. Steffes, F. Solzbacher, and E. Obermeier, "Structural and gas-sensing properties of V2O5–MoO3 thin films for H2 detection," Sens. Actuators B, Chem., vol. 77, pp. 346-351, 2001.
[70] A. Sanger, A. Kumar, A. Kumar, and R. Chandra, "Highly sensitive and selective hydrogen gas sensor using sputtered grown Pd decorated MnO2 nanowalls," Sens. Actuators B, Chem., vol. 234, pp. 8-14, 2016.
[71] H.M. ApSimon, B.M. Barker, and S. Kayin, "Modelling studies of the atmospheric release and transport of ammonia in anticyclonic episodes," Atmospheric Environment, vol. 28, pp. 665-678, 1994.
[72] S. Yamulki, R.M. Harrison, and K.W.T. Goulding, "Ammonia surface-exchange above an agricultural field in Southeast England," Atmospheric Environment, vol. 30, pp. 109-118, 1996.
[73] R.L. Knight, R.H. Kadlec, and H.M. Ohlendorf, "The use of treatment wetlands for petroleum industry effluents," Environ. Sci. Technol., vol. 33, pp. 973-980, 1999.
[74] D. Schönauer-Kamin, M. Fleischer, and R. Moos, "Influence of the V2O5 content of the catalyst layer of a non-nernstian NH3 sensor," Solid State Ionics, vol. 262, pp. 270-273, 2014.
[75] H. Yin, C. Song, Z. Wang, H. Shao, Y. Li, H. Deng, Q. Ma, and K. Yu, "Self-assembled vanadium oxide nanoflakes for p-type ammonia sensors at room temperature," Nanomaterials, vol. 9, pp., 2019.
[76] I. Raible, M. Burghard, U. Schlecht, A. Yasuda, and T. Vossmeyer, "V2O5 nanofibres: novel gas sensors with extremely high sensitivity and selectivity to amines," Sens. Actuators B, Chem., vol. 106, pp. 730-735, 2005.
[77] R. Pandeeswari, and B.G. Jeyaprakash, "High sensing response of β-Ga2O3 thin film towards ammonia vapours: Influencing factors at room temperature," Sens. Actuators B, Chem., vol. 195, pp. 206-214, 2014.
[78] A.A. Akande, T. Mosuang, C.N.M. Ouma, E.M. Benecha, T. Tesfamichael, K. Roro, A.G.J. Machatine, and B.W. Mwakikunga, "Ammonia gas sensing characteristics of V2O5 nanostructures: A combined experimental and ab initio density functional theory approach," J. Alloys Compd., vol. 821, pp. 153565, 2020.
[79] K.-i. Shimizu, I. Chinzei, H. Nishiyama, S. Kakimoto, S. Sugaya, W. Matsutani, and A. Satsuma, "Doped-vanadium oxides as sensing materials for high temperature operative selective ammonia gas sensors," Sens. Actuators B, Chem., vol. 141, pp. 410-416, 2009.
[80] M. Kodu, A. Berholts, T. Kahro, J. Eriksson, R. Yakimova, T. Avarmaa, I. Renge, H. Alles, and R. Jaaniso, "Graphene-based ammonia sensors functionalised with sub-monolayer V2O5: A comparative study of chemical vapour deposited and epitaxial graphene," Sensors, vol. 19, pp., 2019.
[81] N. Singh, A. Umar, N. Singh, H. Fouad, O.Y. Alothman, and F.Z. Haque, "Highly sensitive optical ammonia gas sensor based on Sn doped V2O5 nanoparticles," Mater. Res. Bull., vol. 108, pp. 266-274, 2018.
[82] J. Huotari, R. Bjorklund, J. Lappalainen, and A. Lloyd Spetz, "Pulsed laser deposited nanostructured vanadium oxide thin films characterized as ammonia sensors," Sens. Actuators B, Chem., vol. 217, pp. 22-29, 2015.
[83] J. Wang, P. Zhang, J.-Q. Qi, and P.-J. Yao, "Silicon-based micro-gas sensors for detecting formaldehyde," Sens. Actuators B, Chem., vol. 136, pp. 399-404, 2009.
[84] S. Hussain, N. Aslam, X.Y. Yang, M.S. Javed, Z. Xu, M. Wang, G. Liu, and G. Qiao, "Unique polyhedron CeO2 nanostructures for superior formaldehyde gas-sensing performances," Ceram. Int., vol. 44, pp. 19624-19630, 2018.
[85] E. Menart, V. Jovanovski, and S.B. Hočevar, "Novel hydrazinium polyacrylate-based electrochemical gas sensor for formaldehyde," Sens. Actuators B, Chem., vol. 238, pp. 71-75, 2017.
[86] H.J. Park, N.-J. Choi, H. Kang, M.Y. Jung, J.W. Park, K.H. Park, and D.-S. Lee, "A ppb-level formaldehyde gas sensor based on CuO nanocubes prepared using a polyol process," Sens. Actuators B, Chem., vol. 203, pp. 282-288, 2014.
[87] H. Deng, H.-r. Li, F. Wang, C.-x. Yuan, S. Liu, P. Wang, L.-z. Xie, Y.-z. Sun, and F.-z. Chang, "A high sensitive and low detection limit of formaldehyde gas sensor based on hierarchical flower-like CuO nanostructure fabricated by sol–gel method," Journal of Materials Science: Materials in Electronics, vol. 27, pp. 6766-6772, 2016.
[88] J. Wang, L. Liu, S.-Y. Cong, J.-Q. Qi, and B.-K. Xu, "An enrichment method to detect low concentration formaldehyde," Sens. Actuators B, Chem., vol. 134, pp. 1010-1015, 2008.
[89] Y.M. Zhang, J. Zhang, J.L. Chen, Z.Q. Zhu, and Q.J. Liu, "Improvement of response to formaldehyde at Ag–LaFeO3 based gas sensors through incorporation of SWCNTs," Sens. Actuators B, Chem., vol. 195, pp. 509-514, 2014.
[90] J. Flueckiger, K.F. Ko, and C.K. Cheung, "Microfabricated formaldehyde gas sensors," Sensors, vol. 9, pp., 2009.
[91] X. Ma, J. Shen, D. Hu, L. Sun, Y. Chen, M. Liu, C. Li, and S. Ruan, "Preparation of three-dimensional Ce-doped Sn3O4 hierarchical microsphere and its application on formaldehyde gas sensor," J. Alloys Compd., vol. 726, pp. 1092-1100, 2017.
[92] H. Mu, K. Wang, S. Zhang, K. Shi, S. Sun, Z. Li, J. Zhou, and H. Xie, "Fabrication and characterization of amino group functionalized multiwall carbon nanotubes (MWCNT) formaldehyde gas sensors," IEEE Sensors Journal, vol. 14, pp. 2362-2368, 2014.
[93] J. Huotari, V. Kekkonen, J. Puustinen, J. Liimatainen, and J. Lappalainen, "Pulsed Laser Deposition for Improved Metal-oxide Gas Sensing Layers," Procedia Engineering, vol. 168, pp. 1066-1069, 2016.
[94] S.N. Birajdar, N.Y. Hebalkar, S.K. Pardeshi, S.K. Kulkarni, and P.V. Adhyapak, "Ruthenium-decorated vanadium pentoxide for room temperature ammonia sensing," RSC Advances, vol. 9, pp. 28735-28745, 2019.