本篇論文基於氧化銦鋅薄膜與雙重金屬奈米粒子的結合製備氣體感測器，該感測器將氧化銦鋅薄膜夾在上層鈀、鉑和金三種不同的貴金屬奈米粒子與下層銀奈米粒子之間，形成一種新型的雙金屬夾層結構。銀奈米粒子的加入顯著增加了表面粗糙度，使薄膜的有效感測面積區域增加，而貴金屬奈米顆粒則提升了有效表面區域與催化活性，使氣體感測性能大幅提升。氧化銦鋅薄膜與貴金屬奈米粒子 (鈀、鉑、金)以及銀奈米粒子分別使用射頻磁控濺鍍機與真空熱蒸鍍機所製備而成。元件表面形貌及特性透過掃描式電子顯微鏡、原子力顯微鏡、穿透式電子顯微鏡、X射線光電子能譜儀、能量分散X光譜儀進行分析。

本篇論文共設計並製作了四種不同的氣體感測器，第一種為氧化銦鋅薄膜夾層於上層鈀奈米粒子與下層銀奈米粒子之間的氣體感測器，由於經過鈀奈米粒子的修飾對於氫氣有良好的感測特性，在200℃的環境下，通入濃度為1%的氫氣，可以得到感測響應為2.82×104，響應以及回復時間分別為95秒和17秒，同時對氫氣展現出優異的選擇性。而沒有經過銀奈米粒子修飾的鈀奈米粒子結合氧化銦鋅薄膜感測元件也進行了比較，同樣在200℃的環境下，通入濃度為1%的氫氣，得到的感測響應為8.49×103，由此可知，經過銀奈米粒子修飾過後的感測元件能夠增加表面有效感測面積，使得感測響應大幅提升。

第二種為氧化銦鋅薄膜夾層於上層鉑奈米粒子與下層銀奈米粒子之間的氣體感測器，由於經過鉑奈米粒子的修飾對於氨氣有良好的感測特性，在275℃的環境下，通入濃度為1000 ppm 的氨氣，可以得到感測響應為1.31×103，響應及回復時間為80秒和12秒，同時對氨氣展現出優異的選擇性，並具有低至10 ppb的極限檢測能力。而沒有經過銀奈米粒子修飾的鉑奈米粒子結合氧化銦鋅薄膜感測元件也進行了比較，同樣在275℃的環境下，通入濃度為1000 ppm的氨氣，得到的感測響應為520，由此可知，經過銀奈米粒子修飾過後的感測元件能夠增加表面有效感測面積，使得感測響應大幅提升。

第三種為氧化銦鋅薄膜夾層於上層金奈米粒子與下層銀奈米粒子之間的氣體感測器，由於經過金奈米粒子的修飾對於乙醇有良好的感測特性，在275℃的環境下，通入濃度為1000 ppm 的乙醇，可以得到感測響應為1.29×103，響應及回復時間為27秒和8秒，同時對乙醇展現出優異的選擇性，並具有低至10 ppb的極限檢測能力。而沒有經過銀奈米粒子修飾的金奈米粒子結合氧化銦鋅薄膜感測元件也進行了比較，同樣在275℃的環境下，通入濃度為1000 ppm的乙醇，得到的感測響應為344.9，由此可知，經過銀奈米粒子修飾過後的感測元件能夠增加表面有效感測面積，使得感測響應大幅提升。

第四種為透過重新設計光罩圖案，將前述研究的感測元件整合為一顆多重氣體感測器，能夠同時偵測氫氣、氨氣和乙醇，在275℃的環境下，通入濃度為1%的氫氣、1000 ppm的氨氣和1000 ppm 的乙醇，分別得到的感測響應為1.61×103、16.5和169.7。

本論文共開發了四種不同的氣體感測器，所研究的感測器對對應的氣體展現出良好的感測特性、長期穩定性（90 天），並具有結構簡單、成本低廉及製造過程易於實現等優勢。

In this study, gas sensors are fabricated based on the synthesis of an indium zinc oxide (IZO) thin film combined with bimetallic nanoparticles (NPs). The IZO thin film is sandwiched between an upper layer of three different noble metal NPs—namely palladium (Pd), platinum (Pt), and gold (Au), and a lower layer of silver (Ag) NPs, forming a novel bimetallic sandwich structure. The incorporation of Ag NPs significantly increases the surface roughness, thereby enlarging the effective sensing area of the film. Meanwhile, the noble metal NPs enhance both the effective surface area and catalytic activity, leading to a substantial improvement in gas sensing performance. The IZO thin film, noble metal NPs (Pd, Pt, and Au), and Ag NPs were fabricated using radio frequency (RF) magnetron sputtering and vacuum thermal evaporation (VTE), respectively. The surface morphology and characteristics of the fabricated sensor were analyzed using scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS).

In this study, four different gas sensors were designed and fabricated. The first sensor consists of Pd NP/IZO/Ag NP structure. Due to the decoration with Pd NPs, the sensor demonstrates excellent hydrogen (H2) sensing properties, including a high sensing response (SR) of 2.82×104 when exposed to a 1% H2/air gas, along with response and recovery times of 95 s and 17 s at 200°C, respectively, while exhibiting excellent selectivity for hydrogen. A comparison was made with the Pd NP/IZO sensor that was not decorated with Ag NPs. Under the same conditions (1% H2/air gas at 200°C), the S¬R was 8.49×103. This indicates that the decoration with Ag NPs significantly increases the effective sensing surface area, leading to a substantial improvement in sensing response.

The second sensor consists of Pt NP/IZO/Ag NP structure. Due to the decoration with Pt NPs, the sensor demonstrates excellent ammonia (NH3) sensing properties, including a high SR of 1.31×103 when exposed to a 1000 ppm NH3/air gas, along with response and recovery times of 80 s and 12 s at 275°C, respectively, while exhibiting excellent selectivity for ammonia and a detection limit as low as 10 ppb. A comparison was made with the Pt NP/IZO sensor that was not decorated with Ag NPs. Under the same conditions (1000 ppm NH3/air gas at 275°C), the S¬R was 520. This indicates that the decoration with Ag NPs significantly increases the effective sensing surface area, leading to a substantial improvement in sensing response.

The third sensor consists of Au NP/IZO/Ag NP structure. Due to the decoration with Au NPs, the sensor demonstrates excellent ethanol (C2H5OH) sensing properties, including a high SR of 1.29×103 when exposed to a 1000 ppm C2H5OH/air gas, along with response and recovery times of 27 s and 8 s at 275°C, respectively, while exhibiting excellent selectivity for ethanol and a detection limit as low as 10 ppb. A comparison was made with the Au NP/IZO sensor that was not decorated with Ag NPs. Under the same conditions (1000 ppm C2H5OH/air gas at 275°C), the S¬R was 344.9. This indicates that the decoration with Ag NPs significantly increases the effective sensing surface area, leading to a substantial improvement in sensing response.

The fourth sensor was developed by integrating the three previously discussed gas sensors into a single multi-gas sensor through a redesigned photomask pattern. This integrated sensor is capable of detecting hydrogen, ammonia, and ethanol simultaneously. As a result, when exposed to 1% H2/air, 1000 ppm NH3/air, and 1000 ppm C2H5OH/air, the respective sensing responses were 1.61×10³, 16.5, and 169.7 at 275°C.

In this work successfully developed four different gas sensors, each demonstrating excellent sensing performance, long-term stability (90 days), and notable advantages, including a simple structure, low fabrication cost, and ease of manufacturing.

[1] Y. C. Yang, J.S. Niu, and W.C. Liu, “Study of a palladium nanoparticle/indium oxide-based hydrogen gas sensor,” IEEE Trans. Electron Devices, Vol. 69, pp. 318-324, 2021.
[2] H. T. Wang, B. S. Kang, F. Ren, L.C. Tien, P. W. Sadik, D. P. Norton, S. J. Pearton, and J. Lin, “Hydrogen-selective sensing at room temperature with ZnO nanorods,” Appl. Phys. Lett., vol. 86, pp. 243503, 2005.
[3] Y. Shimizu, N. Kuwano, T. Hyodo, and M. Egashira, “High H2 sensing performance of anodically oxidized TiO2 film contacted with Pd,” Sens. Actuators B Chem., vol. 83, no. 1, pp. 195-201, Mar. 2022.
[4] Y. H. Choi, D. H. Kim, S. H. Hong, and K. S. Hong, “H2 and C2H5OH sensing characteristics of mesoporous p-type CuO films prepared via a novel precursor-based ink solution route,” Sens. Actuators B Chem., vol. 178, pp. 395-403, 2013.
[5] H. Steinebach, S. Kannan, L. Rieth, and F. Solzbacher, “H2 gas sensor performance of NiO at high temperatures in gas mixtures, Sens. Actuators B Chem., vol. 151, no. 1, pp. 162-168, 2010.
[6] K. Ramamoorthy, K. Kumar, R. Chandramohan, and K. Sankaranarayanan, “Review on material properties of IZO thin films useful as epi-n-TCOs in opto-electronic (SIS solar cells, polymeric LEDs) devices,” Mater. Sci. Eng. B, vol. 126, pp. 1-15, 2006.
[7] P. Barquinha, G. Goncalves, L. Pereira, R. Martins, and E. Fortunato, “Effect of annealing temperature on the properties of IZO films and IZO based transparent TFTs,” Thin Solid Films, vol. 515, pp. 8450-8454, 2007.
[8] D. C. Tsai, Z. C. Chang, B. H. Kuo, Y. H. Wang, E. C. Chen, and F. S. Shieu, “Thickness dependence of the structural, electrical, and optical properties of amorphous indium zinc oxide thin films,” J. Alloys Compd., vol. 743, pp. 603-609, 2018.
[9] R. Martins, P. Barquinha, A. Pimentel, L. Pereira, and E. Fortunato, “Transport in high mobility amorphous wide band gap indium zinc oxide films,” Phys. Status Solidi A, vol. 202, pp. R95-R97, 2005.
[10] P. C. Chou, H. I. Chen, I. P. Liu, C. C. Chen, J. K. Liou, K. S. Hsu, and W. C. Liu, “On the ammonia gas sensing performance of a RF sputtered NiO thin-film sensor,” IEEE Sens. J., vol. 15, pp. 3711-3715, 2015.
[11] S. K. Lee, D. Chang, and S.W. Kim, “Gas sensors based on carbon nanoflake/tin oxide composites for ammonia detection,” J. Hazard. Mater., vol. 268, pp. 110-114, 2014.
[12] C. H. Chang, T. C. Chou, W. C. Chen, J. S. Niu, K. W. Lin, S. Y. Cheng, W. C. Liu, “Study of a WO3 thin film based hydrogen gas sensor decorated with platinum nanoparticles,” Sens. Actuators B Chem., 317 (2020) 128145.
[13] S. J. Teichner, “Recent studies in hydrogen and oxygen spillover and their impact on catalysis,” Appl. Catal., vol. 62, pp. 1-10, 1990.
[14] W. Karim, C. Spreafico, A. Kleibert, J. Gobrecht, J. V, Vondele, Y. Ekinci, and J. A. van Bokhoven, “Catalyst support effects on hydrogen spillover,” Nature, vol. 541, pp.68-71, 2017.
[15] U. Roland, A. Hebestreit, A. Taoussanis, M. Eiserbeck, F. Holzer, A. Wotzka, and S. Wohlrab, “Cost-effective selective hydrogen sensor based on the combination of catalytic spillover effect and impedance measurement,” Int. J. Hydrogen Energy, vol. 48, pp. 37550-37562, 2013.
[16] R. Ab Kadir, Z. Li, A.Z. Sadek, R. Abdul Rani, A.S. Zoolfakar, M.R. Field, J.Z. Ou, A.F. Chrimes, and K. Kalantar-zadeh, “Electrospun granular hollow SnO2 nanofibers hydrogen gas sensors operating at low temperatures,” J. Phys. Chem. C, vol. 118, pp. 3129-3139, 2014.
[17] N. Yamazone, K. Suematsu, and K. Shimanoe, “Surface chemistry of neat tin oxide sensor for response to hydrogen gas in air,” Sens. Actuators B Chem., vol. 227, pp. 403-410, 2016.
[18] H. Chang, T. Chou, W. Chen, J. S. Niu, K. W. Lin, S. Y. Cheng, and W. C. Liu, “Study of a WO3 thin film based hydrogen gas sensor decorated with platinum nanoparticles,” Sens. Actuators B Chem., vol. 317, pp. 128145, 2020.
[19] C.S. Rout, M. Hegde, A. Govindaraj, and C. Rao, “Ammonia sensors based on metal oxide nanostructures,” Nanotechnology, vol. 18, pp. 205504, 2007.
[20] M. Stankova, X. Vilanova, E. Llobet, J. Calderer, C. Bittencourt, J.-J. Pireaux, and X. Correig, “Influence of the annealing and operating temperatures on the gas-sensing properties of rf sputtered WO3 thin-film sensors,” Sens. Actuators B Chem., vol. 105, pp. 271-277, 2005.
[21] P. S. Kuchi, H. Roshan, and M. H. Sheikhi, “A novel room temperature ethanol sensor based on PbS:SnS2 nanocomposite with enhanced ethanol sensing properties,” J. Alloys Compd., vol. 816, pp. 152666, 2020.
[22] A. Zuttel, A. Remhof, A. Borgschulte, and O. Friedrichs, “Hydrogen: the future energy carrier,” Phil. Trans. R. Soc. A, vol. 368, pp. 3329-3342, 2010.
[23] F. Martins, C. Felgueiras, and M. Smitkova, “Fossil fuel energy consumption in european countries,” Energy Procedia., vol. 153, pp. 107-111, 2018.
[24] T. M. Letcher, “1 - Introduction with a focus on atmospheric carbon dioxide and climate change,” Future Energy (Third Edition), pp. 3-17, 2020.
[25] N. Armaroli and Vincenzo Balzani, “The hydrogen issue,” Chem. Eur. J., vol. 4, pp. 21-36, 2011.
[26] N. Kalfagiannis, P.G. Karagiannidis, C. Pitsalidis, N.T. Panagiotopoulos, C. Gravalidis, S. Kassavetis, P. Patsalas, and S. Logothetidis, “Plasmonic silver nanoparticles for improved organic solar cells,” Sol. Energy Mater. Sol. Cells, vol. 104, pp. 165-174, 2012.
[27] C. Y. Cho, M. K. Kwon, S. J. Lee, S. H. Han, J. W. Kang, S. E. Kang, D. Y. Lee, and S. J. Park, “Surface plasmon-enhanced light-emitting diodes using silver nanoparticles embedded in p-GaN,” Nanotechnology, vol. 21, pp. 205201, 2010.
[28] M. K. Shukla, R. P. Singh, C. R. K. Reddy, and B. Jha, “Synthesis and characterization of agar-based silver nanoparticles and nanocomposite film with antibacterial applications,” Bioresour. Technol., vol. 107, pp. 295-300, 2012.
[29] R. Y. Peng and W. C. Liu, “Study of a high-performance chemoresistive ethanol gas sensor synthesized with au nanoparticles and an amorphous IGZO thin film,” IEEE Trans. Electron Devices, vol. 68, pp. 753-760, 2020.
[30] A. Sutka, M. Stingaciu, G. Mezinskis, and A. Lusis, “An alternative method to modify the sensitivity of p-type NiFe2O4 gas sensor,” J. Mater. Sci., vol. 47, pp. 2856-2863, 2012.
[31] C. C. Hsu, J. S. Niu, and W. C. Liu, “Hydrogen sensing properties of a tin dioxide thin film incorporated with evaporated palladium nanoparticles,” ECS J. Solid State Sci. Technol., vol. 11, pp. 027001, 2024.
[32] K. H. Luo, I. P. Liu, C. C. Chiu, K. W. Lin, W. C. Hsu, and W. C. Liu, “Comprehensive study of formaldehyde gas sensing performance of a GTO thin film incorporated with gold nanoparticles,” Sens. Actuators B Chem., vol. 398, pp. 134770, 2024.
[33] P. Cao, Z. Yang, S. T. Navale, S. Han, X. Liu, W. Liu, Y. Lu, F. J. Stadler, and D. Zhu, “Ethanol sensing behavior of Pd-nanoparticles decorated ZnO-nanorod based chemiresistive gas sensors,” Sens. Actuators B Chem., vol. 298, pp. 126850, 2019.
[34] S. S. Badadhe and I. S. Mulla, “H2S gas sensitive indium-doped ZnO thin films: Preparation and characterization,” Sens. Actuators B Chem., vol. 143, pp. 164-170, 2009.
[35] L. Zhang, Q. Guo, Q. Tan, Z. Fan, and J. Xiong, “High performance amorphous IGZO thin-film transistor based on alumina ceramic,” IEEE Access., vol. 7, pp. 184312-184319, 2019.
[36] A. Mirzaei, K. Janghorban, B. Hashemi, M. Bonyani, S. G. Leonardi, and G. Neri, “A novel gas sensor based on Ag/Fe2O3 core-shell nanocomposites,” Ceram. Int., vol. 42, pp. 18974-18982, 2016.
[37] H. Zhang, Y. Wang, Y. Wang, J. Cao, P. Kang, Q. Tang, and M.Ma, “Highly dispersed PdNPs/α-Al2O3 catalyst for the selective hydrogenation of acetylene prepared with monodispersed Pd nanoparticles,” Catalysts, vol. 7, pp. 128, 2017.
[38] C. Lee and W. C. Liu, “A high-performance Pd nanoparticle (NP)/WO3 thin-film-based hydrogen sensor,” IEEE Electron Device Lett., vol. 40, pp. 1194-1197, 2019.
[39] P. S. Lin, J. S. Niu, and W. C. Lin, “Hydrogen sensing properties of an aluminum-doped zinc oxide layer decorated with palladium nanoparticles,” IEEE Electron Device Lett., vol. 43, pp. 280-283, 2021.
[40] J. S. Niu, R. Y. Peng, C. C. Chiu, J. H. Tsai, W. C. Hsu, K. W. Lin, and W. C. Liu, “Comprehensive study of hydrogen gas sensing performance of an amorphous In-Al-Zn-O (a-IAZO) thin film synthesized with Pd nanoparticles,” IEEE Trans. on Electron Devices, vol. 70, pp. 4837-4842, 2023.
[41] C. C. Chen, H. I. Chen, I. P. Liu, H. Y. Liu, P. C. Chou, J. K. Liou, et al, “Enhancement of hydrogen sensing performance of a GaN-based Schottky diode with a hydrogen peroxide surface treatment,” Sens. Actuators B, Chem., vol. 211, p. 303-309, 2015.
[42] T. H. Tsai, J. R. Huang, K. W. Lin, W. C. Hsu, H. I. Chen, and W. C. Liu, “Improved hydrogen sensing characteristics of a Pt/SiO2/GaN Schottky diode,” Sens. Actuators B Chem., vol. 129, pp. 292-302, 2008.
[43] J. R. Huang, W. C. Hsu, H. I. Chen, and W. C. Liu, “Comparative study of hydrogen sensing characteristics of a Pd/GaN Schottky diode in air and N2 atmosphere,” Sens. Actuators B Chem., vol. 123, pp. 1040-1048, 2007.
[44] B. Y. Ke and W. C. Liu, “Enhancement of hydrogen sensing performance of a Pd nanoparticle/Pd film/GaOx/GaN-based metal-oxide-semiconductor diode,” IEEE Trans. Electron Devices, vol. 65, pp. 4577-4584, 2018.
[45] C. F. Chang, T. H. Tsai, H.I. Chen, K. W. Lin, T. P. Chen, L. Y. Chen, Y. C. Liu, and W. C. Liu, “Hydrogen sensing properties of a Pd/SiO2/AlGaN-based MOS diode,” Electrochem. Commun., vol. 11, pp. 65-67, 2009.
[46] T. H. Tsai, H. L. Chen, K. W. Lin, Y. W. Kuo, C. F. Chang, C. W. Hung. L. Y. Chen, T. P. Chen, Y. C. Liu, and W. C. Liu, “SiO2 passsivation effect on the hydrogen adsorption performance of a Pd/AlGaN-based Schottky diode,” Sens. Actuators B Chem., vol. 136, pp. 338-343, 2009.
[47] H. I. Chen, Y. I. Chou, and C. K. Hsiung, “Comprehensive study of adsorption kinetics for hydrogen sensing with an electroless-plated Pd–InP Schottky diode,” Sens. Actuators B Chem., vol. 92, pp. 6-16, 2003.
[48] S. Yamulki, R. M. Harrison, and K. W. T. Goulding, “Ammonia surface-exchange above an agricultural field in Southeast England,” Atmos. Environ., vol. 30, pp. 109–118, 1996.
[49] Q. Wang, H. Fu, J. Ding, C. Yang, and S. Wang, “Sensitivity enhanced microfiber interferometer ammonia gas sensor by using WO3 nanorods coatings,” Opt. Laser Technol., vol. 125, pp. 106036, 2020.
[50] V. Felipo and R. F. Butterworth, “Neurobiology of ammonia,” Prog. Neurobiol., vol. 67, pp. 259-279, 2002.
[51] M. P. Diana, W. S. Roekmijati, and W. U. Suyud, “Why it is often underestimated: historical study of ammonia gas exposure impacts towards human health,” E3S Web Conf., vol. 73, pp. 06003, 2018.
[52] X. Fu, Y. Wang, N. Wu, L. Gui, and Y. Tang, “Surface modification of small platinum nanoclusters with alkylamine and alkylthiol: an XPS study on the influence of organic ligands on the Pt 4f binding energies of small platinum nanoclusters,” J. Colloid Interface Sci., vol. 243(2), pp. 326-330, 2001.
[53] A. F. Lee, D. E. Gawthrope, N. J. Hart, and K. Wilson, “A Fast XPS study of the surface chemistry of ethanol over Pt {1 1 1}.” Surf. Sci., vol. 548(1-3), pp. 200-208, 2004.
[54] N. Markovic, and P. N. Ross, “Effect of anions on the underpotential deposition of copper on platinum (111) and platinum (100) surfaces.” Langmuir, vol. 9(2), pp. 580-590, 1993.
[55] T. He, W. Wang, F. Shi, X. Yang, X. Li, J. Wu, and M. Jin, “Mastering the surface strain of platinum catalysts for efficient electrocatalysis,” Nature, vol. 598(7879), pp. 76-81, 2021.
[56] B. X. Zhu, C. C. Chiu, J. J. Jian, K. W. Lin, W. C. Hsu, and W. C. Liu, “Ammonia Sensing Performance of an Al-Doped SnO2 Thin Film Decorated With Platinum Nanoparticles,” IEEE Electron Device Lett., vol. 44, pp. 2043-2046, 2023.
[57] T. Liu, T. Wang, H. Li, J. Su, X. Hao, F. Liu, F. Liu, and X. Liang, “Ethanol sensor using gadolinia-doped ceria solid electrolyte and double perovskite structure sensing material,” Sens. Actuators B Chem., vol. 349, pp. 130771, 2021.
[58] S. Mukherjee, S. K. Das , and D. M. Vasudevan, “Effects of Ethanol Consumption on Different Organs-A Brief Overview,” Asian J. Biochem., vol. 2, pp. 386-394, 2007.
[59] M. Sukhes, “Alcoholism and its Effects on the Central Nervous System,” Curr. Neurovasc. Res., vol. 10, pp. 256-262(7), 2018.
[60] M. Mitu and E. Brandes, “Influence of pressure, temperature and vessel volume on explosion characteristics of ethanol/air mixtures in closed spherical vessels,” Fuel, vol. 203, pp. 460-468, 2017.
[61] A. Y. Klyushin, T. C. Rocha, M. Hävecker, A. Knop-Gericke, and R. Schlögl, “A near ambient pressure XPS study of Au oxidation,” Phys. Chem. Chem. Phys., vol. 16, pp. 7881-7886, 2014.
[62] P. X. Huang, F. Wu, B. L. Zhu, X. P. Gao, H. Y. Zhu, T. Y. Yan, and D. Y. Song, “CeO2 nanorods and gold nanocrystals supported on CeO2 nanorods as catalyst,” J. Phys. Chem. B, vol. 109, pp. 19169-19174, 2005.
[63] L. Chen, X. He, Y. Liang, Y. Sun, Z. Zhao, and J. Hu, “Synthesis and gas sensing properties of palladium-doped indium oxide microstructures for enhanced hydrogen detection,” J. Mater. Sci. Mater. Electron., vol. 27, pp. 11331-11338, 2016.
[64] O. Lupan, V. Postica, N. Ababii, M. Hoppe, V. Cretu, I. Tiginyanu, V. Sontea, T. Pauport´e, B. Viana, and R. Adelung, “Influence of CuO nanostructures morphology on hydrogen gas sensing performances,” Microelectron. Eng., vol. 164, pp. 63-70, 2016.
[65] N. V. Toan, N. V. Chien, N. V. Duy, H. S. Hong, H. Nguyen, N. D. Hoa, and N. V. Hieu, “Fabrication of highly sensitive and selective H2 gas sensor based on SnO2 thin film sensitized with microsized Pd islands,” J. Hazard. Mater., vol. 301, pp. 433-422, 2016.
[66] S. M. Mohammad, Z. Hassan, R. A. Talib, N. M. Ahmed, M. A. Al-Azawi, N. M. AbdAlghafour, C.W. Chin, and N. H. Al-Hardan, “Fabrication of a highly flexible low-cost H2 gas sensor using ZnO nanorods grown on an ultra-thin nylon substrate,” J. Mater. Sci.: Mater. Electron., vol. 27, pp. 9461-9469, 2016.
[67] T. T. L. Dang, M. Tonezzer, and V. H. Nguyen, “Hydrothermal growth and hydrogen selective sensing of nickel oxide nanowires,” J. Nanomater., vol. 2015, pp. 785856, 2015.
[68] E. Amani and K. Khojier, “Improving the hydrogen gas sensitivity of WO3 thin films by modifying the deposition angle and thickness of different promoter layers,” Int. J. Hydrog. Energy, vol. 42, pp. 29620-29628, 2017.
[69] N. Pradeep, C. Venkatachalaiah, U. Venkatraman, C. Santhosh, A. Bhatnagar, S. K. Jeong, and A.N. Grace, “Magnesium oxide nanocubes deposited on an overhead projector sheet: synthesis and resistivity-based hydrogen sensing capability,” Microchim. Acta, vol. 184, pp. 3349-3355, 2017.
[70] Y. C. Yang, J.S. Niu, and W.C. Liu, “Study of a palladium nanoparticle/indium oxidebased hydrogen gas sensor,” IEEE Trans. Electron Devices., vol. 69, pp. 318-324, 2021.
[71] X. Luo, K. You, Y. Hu, S. Yang, X. Pan, Z. Wang, W. Chen, and H. Gu, “Rapid hydrogen sensing response and aging of α-MoO3 nanowires paper sensor,” Int. J. Hydrog. Energy., vol. 42, pp. 8399-8405, 2017.
[72] O. V. Anisimov, N. K. Maksimova, E. V. Chernikov, E. Y. Sevastyanov, and N. V. Sergeychenko, “Sensitivity to NH3 of SnO2 thin films prepared by magnetron sputtering.” IEEE SIBCON, pp. 189-193, 2009.
[73] Z. Tian, P. Song, Z. Yang, and Q. Wang, “Reduced graphene oxide-porous In2O3 nanocubes hybrid nanocomposites for room-temperature NH3 sensing,” Chin. Chem. Lett., vol. 31, pp. 2067-2070, 2020.
[74] G. D. Khuspe, S. T. Navale, M. A. Chougule, V. B. Patil, “Ammonia gas sensing properties of CSA doped PANi-SnO2 nanohybrid thin films,” Synth. Met., vol. 185, pp. 1-8, 2013.
[75] D. Punetha and S. K. Pandey, “Sensitivity enhancement of ammonia gas sensor based on hydrothermally synthesized rGO/WO3 nanocomposites.” IEEE Sens. J., vol. 20(4), pp. 1738-1745, 2019.
[76] Y. Wang, J. Liu, X. Cui, Y. Gao, Y. Sun, and G. Lu, “NH3 gas sensing performance enhanced by Pt-loaded on mesoporous WO3,” Sens. Actuators B Chem., vol. 238, pp. 473-481, 2017.
[77] S. J. Chang, W. Y. Weng, C. L. Hsu, and T. J. Hsueh, “High sensitivity of a ZnO nanowire-based ammonia gas sensor with Pt nano-particles,” Nano Commun Netw. J., vol. 1, no. 4, pp. 283-288, 2010.
[78] S. Bhuvaneshwari and N. Gopalakrishnan, “Hydrothermally synthesized Copper Oxide (CuO) superstructures for ammonia sensing,” J. Colloid Interface Sci., vol. 480, pp. 78-84, 2016.
[79] C. W. Lin, H. I. Chen, T. Y. Chen, C. C. Huang, C. S. Hsu, R. C. Liu, and W. C. Liu, “On an indium–tin-oxide thin film based ammonia gas sensor,” Sens. Actuators B Chem., vol. 160, pp. 1481-1484, 2011. “”
[80] J. H. Tsai, J. S. Niu, W. C. Shao, and W. C. Liu, “Characteristics of chemiresistive-type ammonia sensor based on Ga2O3 thin film functionalized with platinum nanoparticles. Sens. Actuators B Chem., vol. 371, pp. 132589, 2022.
[81] J. Guo and C. Peng,“Synthesis of ZnO nanoparticles with a novel combustion method and their C2H5OH gas sensing properties,” Ceram. Int., vol. 41, no. 2, pp. 2180-2186, 2015.
[82] C. W. Na, H. S. Woo, I. D. Kim, and J. H. Lee,“ Selective detection of NO2 and C2H5OH using a Co3O4-decorated ZnO nanowire network sensor,” Chem. Commun., vol. 47, pp. 5148-5150, 2011.
[83] X. Liu, J. Zhang, X. Guo, S. Wu, and S. Wang,“ Porous α-Fe2O3 decorated by au nanoparticles and their enhanced sensor performance,” Nanotechnology, vol. 21, no. 9, pp. 095501, 2010.
[84] Z. Wei, M. K. Akbrari, Z. Hai, R. K. Ramachandran, C. Detavernier, F. Verpoort, E. Kats, H. Xu, J. Hu, and S. Zhuiykov, “Ultra-thin sub-10 nm Ga2O3-WO3 heterostructures developed by atomic layer deposition for sensitive and selective C2H5OH detection on ppm level,” Sens. Actuators B Chem., vol. 287, pp. 147-156, 2019.
[85] S. Yan, J. Xue, and Q. Wu, “Synchronous synthesis and sensing performance of α-Fe2O3/SnO2 nanofiber heterostructures for conductometric C2H5OH detection,” Sens. Actuators B, Chem., vol. 275, pp. 322-331, 2018.
[86] Z. wang, Z. Tian, D. Han, and F. Gu, “Highly Sensitive and Selective Ethanol Sensor Fabricated with In-Doped 3DOM ZnO,” ACS Appl. Mater. Interfaces, vol. 8, pp. 5466-5474, 2016.
[87] K. W. Kim, P. S. Cho, S. J. Kim, J. H. Lee, C. Y. Kang, J. S. Kim, and S. J. Yoon,“ The selective detection of C2H5OH using SnO2–ZnO thin film gas sensors prepared by combinatorial solution deposition,” Sens. Actuators B Chem., vol. 123, no. 1, pp. 318-324, 2007.
[88] H. Zhao, Y. Li, L. Yang, and X. Wu, Synthesis, “characterization and gas-sensing property for C2H5OH of SnO2 nanorods,” Mater. Chem. Phys., vol. 112, no. 1, pp. 244-248, 2008.
[89] H. Chen, W. Jiang, L. Zhu, and Y. Yao, “Amorphous In–Ga–Zn–O powder with high gas selectivity towards wide range concentration of C2H5OH,” Sensors, vol. 17, pp. 1203, 2017.
[90] C. C. Chiu, P. Y. Chu, G. J. Chiu, S. W. Tan, and W. C. Liu, “Investigation of Ethanol Sensing Properties of a Sputtered InZnO Thin Layer Synthesized with Evaporated Gold Nanoparticles,” IEEE Sens. J., vol. 24, pp.39643-39650, 2024
[91] C. C. Chiu, C. K. Kuo, P. Y. Chu, D. H. Shih, and W. C. Liu, “Study of a palladium nanoparticle/In-Zn-O thin film-based hydrogen gas sensor,” Sens. Actuators B Chem., vol. 415, pp. 136015, 2024.