本研究於四吋矽基板上以低溫水熱法成長氧化鋅奈米柱，接著以光還原法將銅氧化物修飾於氧化鋅奈米柱表面，從而製作出銅氧化物/氧化鋅奈米複合材料感測晶片，並對此感測晶片進行6種不同氣體感測、穩定度測試及戶外場域測試。
在進行氣體感測前我們先對材料進行分析。首先使用掃描式電子顯微鏡(SEM)確認材料的表面情況，其中氧化鋅六角柱體長度約為2 µm、直徑約為100 nm，而銅氧化物奈米團簇則成長於氧化鋅柱頂端並具有400 nm左右的直徑。之後使用能量散射X-射線光譜儀(EDS)及X-射線光電子光譜儀(XPS)對材料進行元素分析，確認材料的元素組成及銅氧化物中銅元素的價態比例。然後以X-射線繞射分析儀(XRD)對材料進行晶體結構分析，確認氧化鋅及銅氧化物的結晶情況。最後用螢光光譜儀(PL)確認材料的光學性質及缺陷組成。
在光活化模式下對感測晶片進行氣體感測的實驗結果顯示，感測晶片在臭氧濃度為500 ppb以下時，其線性靈敏度可達57.5 ppm1，而同濃度條件下測得之二氧化氮靈敏度則為4.63 ppm1，至於其餘4種常見氣體的靈敏度則更低(<1 ppm1)，顯示感測晶片對臭氧氣體的高選擇性。對感測晶片進行長時間測試，感測晶片在歷經一個月的室內環境下其穩定電阻變化不大，而對臭氧靈敏度變化更是趨近於零，證明其長時間運作的可靠性。最後將感測晶片置於不同濕度環境下進行臭氧感測，檢視其是否能在台灣的高濕度下正常運作，也得到不錯的結果。
進一步在實際戶外場域測試，將此感測晶片與可攜式氣體感測器置於新北市永和環保署測站旁進行場域測試，配合環保署數據並使用人工神經網路進行氣體濃度預測。通過使用一個禮拜的數據做為模型的訓練，並用後續一個月的數據進行氣體濃度預測，在以臭氧為預測目標的條件下，其預測結果和環保署數據相比決定係數可達0.382；而在以0.9 O3 + 0.1 NO2此一接近實驗所得的氣體選擇性為預測目標情況下，其預測結果決定係數更可高達0.41。
綜合以上結果，本研究證明銅氧化物/氧化鋅複合材料可以被有效地進行大面積成長製作，並有極高的潛力作為高靈敏度感測晶片來應用於環境臭氧濃度監測。

In this work, CuxO/ZnO nanocomposites gas sensing chips are fabricated by first growing ZnO nanorods on 4” silicon substrates through a low-temperature hydrothermal method, and then depositing CuxO on the surface of the ZnO nanorods by photoreduction method. These fabricated CuxO/ZnO sensing chips are then performed gas sensing tests for six different kinds of gases. In addition, long-term stability and outdoor field performance are also investigated.
Before gas sensing, first we need to analyze the material properties. X-ray diffractometer (XRD) was used to examine crystal structure of the material to confirm the crystallization of ZnO and CuxO. Scanning electron microscope (SEM) was used for morphology analysis of the materal. The ZnO hexagonal nanorods are about 2 µm in length and 100 nm in diameter, while the CuxO nanoclusters grow on top of the ZnO and have a diameter about 400 nm. Energy dispersive X-ray spectrometer (EDS) and X-ray photoelectron spectrometer (XPS) were used for elemental analysis and determination of Cu2+/Cu+ ratio. Finally, fluorescence spectrometer (PL) was used to confirm the optical properties and defect composition of the material.
Experimentally, gas sensing measurements are performed under photo-activation mode. Results show that linear sensitivity of ozone (O3) reaches up to 57.5 ppm–1 for the O3 concentration below 500 ppb, while in the case of nitrogen dioxide (NO2) the obtained sensitivity value is only 4.63 ppm–1. Furthermore, it is found that sensitivity values of other four different gases are much lower than that of O3. These results prove that CuxO/ZnO sensor has very high selectivity toward O3 gas. For further stability testing, sensor chips are monitored for a one-month period under an indoor environment condition. The base resistance and response of sensor chips are almost stable and not showing much change, indicating good reliability over a long-term operation. These sensor chips are also placed in different humidity environments and then checked for gas sensing response toward O3. Comparable results are obtained at different humidity conditions.
For field test, CuxO/ZnO sensing chip is installed in a smart phone-operated portable gas sensing device. This portable device is then installed at the Yonghe Environmental Protection Agency (EPA) station in New Taipei City for field testing. Gas concentration is predicted from collected data, utilizing artificial neural networks (ANN) computation by setting O3 as the prediction target and taking one week's data for model training and the following month's data for gas concentration prediction. Compared with EPA data the coefficient of determination of the prediction result can reach well to a value of 0.382. When gas selectivity of a gas mixture (0.9 × O3 + 0.1 × NO2) is chosen as the prediction target, then the coefficient of determination of the prediction result can be as high as 0.41.
According to the above mentioned, this research shows that CuxO/ZnO binary composite can be effectively grown on large scale and proves to have a very high potential as a highly sensitive O3 sensor for real time air quality monitoring.

摘要 I
Abstract III
致謝 VI
目錄 VII
圖目錄 XII
表目錄 XV
第一章 緒論 2
1.1 前言 2
1.2 研究動機 4
第二章 文獻回顧 5
2.1 氣體感測器 5
2.1.1氣體感測器基本性質 5
2.1.2氣體感測器種類 6
2.2 金屬氧化物半導體氣體感測器 7
2.2.1金屬氧化物半導體感測機制 7
2.2.2 臭氧吸附機制 10
2.2.3 光激發脫附機制 11
2.3 氧化鋅概論 13
2.3.1 氧化鋅晶體結構 13
2.3.2 氧化鋅奈米柱的合成機制 15
2.3.3 氧化鋅n-type半導體特性 16
2.3.4 氧化鋅的光致發光性質 17
2.4 複合材料之氣體感測 19
2.4.1 金屬氧化物修飾 20
2.5 光沉積 22
2.5.1 銅氧化物修飾 22
第三章 實驗方法與儀器 24
3.1 實驗設計 24
3.2 感測元件製作 25
3.2.1 基板電極製作 25
3.2.2 氧化鋅奈米線成長 25
3.2.3 銅氧化物修飾 27
3.3 材料分析儀器 29
3.3.1 掃描式電子顯微鏡 29
3.3.2 能量色散X-射線光譜儀 29
3.3.3 X-射線光電子光譜儀 29
3.3.4 X-射線繞射分析儀 29
3.3.5 螢光光譜儀 30
3.4 氣體感測 30
3.4.1 流動式系統 30
3.4.2 封閉式系統 33
3.4.2.1 二氧化氮/一氧化氮/氨氣感測系統 33
3.4.2.2 甲醇感測系統 35
3.4.2.3 甲醛感測系統 36
3.4.2.4 不同濕度環境之臭氧感測系統 39
3.4.2.5 封閉式系統氣體濃度計算 41
3.5 戶外場域感測 44
3.5.1 可攜式氣體感測器 45
第四章 結果與討論 47
4.1 材料分析 47
4.1.1 表面形貌 47
4.1.2 元素成分分析 49
4.1.3 晶體結構 51
4.1.4 光致發光性質分析 52
4.2 氣體感測結果 53
4.2.1 臭氧氣體感測 54
4.2.2 二氧化氮氣體感測 56
4.2.3 一氧化氮氣體感測 57
4.2.4 氨氣氣體感測 58
4.2.5 甲醇氣體感測 59
4.2.6 甲醛氣體感測 60
4.2.7 選擇性結果統整 62
4.3 相對溼度對臭氧感測的影響 63
4.4 感測晶片長時間穩定性 64
4.5戶外場域測試 65
4.5.1 人工神經網路計算 67
第五章 結論 73
參考文獻 75

1. WHO global air quality guidelines: particulate matter (PM2. 5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide; World Health Organization, 2021.

2. Altshuller, A. Estimation of the natural background of ozone present at surface rural locations. Journal of Air Pollution Control Association 1987, 37 (12), 1409-1417.

3. Lippmann, M. Health effects of ozone a critical review. Journal of Air Pollution Control Association 1989, 39 (5), 672-695.

4. Medina-Ramon, M.; Zanobetti, A.; Schwartz, J. The effect of ozone and PM10 on hospital admissions for pneumonia and chronic obstructive pulmonary disease: a national multicity study. American Journal of Epidemiology 2006, 163 (6), 579-588.

5. Bochenkov, V.; Sergeev, G. Sensitivity, selectivity, and stability of gas-sensitive metal-oxide nanostructures. Metal Oxide Nanostructures and Their Applications 2010, 3, 31-52.

6. Hulanicki, A.; Glab, S.; Ingman, F. Chemical sensors: definitions and classification. Pure and Applied Chemistry 1991, 63 (9), 1247-1250.

7. Hodgkinson, J.; Tatam, R. P. Optical gas sensing: a review. Measurement Science and Technology 2012, 24 (1), 012004.

8. Bakker, E.; Telting-Diaz, M. Electrochemical sensors. Analytical Chemistry 2002, 74 (12), 2781-2800.

9. Srinivasan, P.; Ezhilan, M.; Kulandaisamy, A. J.; Babu, K. J.; Rayappan, J. B. B. Room temperature chemiresistive gas sensors: Challenges and strategies—A mini review. Journal of Materials Science: Materials in Electronics 2019, 30 (17), 15825-15847.

10. Simon, I.; Bârsan, N.; Bauer, M.; Weimar, U. Micromachined metal oxide gas sensors: opportunities to improve sensor performance. Sensors and Actuators B: Chemical 2001, 73 (1), 1-26.

11. Miller, D. R.; Akbar, S. A.; Morris, P. A. Nanoscale metal oxide-based heterojunctions for gas sensing: a review. Sensors and Actuators B: Chemical 2014, 204, 250-272.

12. Liao, L.; Lu, H.; Li, J.; He, H.; Wang, D.; Fu, D.; Liu, C.; Zhang, W. Size dependence of gas sensitivity of ZnO nanorods. The Journal of Physical Chemistry C 2007, 111 (5), 1900-1903.

13. Kumar, R.; Al-Dossary, O.; Kumar, G.; Umar, A. Zinc oxide nanostructures for NO2 gas–sensor applications: a review. Nano-Micro Letters 2015, 7 (2), 97-120.

14. Wagner, T.; Sauerwald, T.; Kohl, C.-D.; Waitz, T.; Weidmann, C.; Tiemann, M. Gas sensor based on ordered mesoporous In2O3. Thin Solid Films 2009, 517 (22), 6170-6175.

15. Zhang, J.; Wang, S.; Wang, Y.; Wang, Y.; Zhu, B.; Xia, H.; Guo, X.; Zhang, S.; Huang, W.; Wu, S. NO2 sensing performance of SnO2 hollow-sphere sensor. Sensors and Actuators B: Chemical 2009, 135 (2), 610-617.

16. Meng, D.; Yamazaki, T.; Shen, Y.; Liu, Z.; Kikuta, T. Preparation of WO3 nanoparticles and application to NO2 sensor. Applied Surface Science 2009, 256 (4), 1050-1053.

17. Inoue, T.; Ohtsuka, K.; Yoshida, Y.; Matsuura, Y.; Kajiyama, Y. Metal oxide semiconductor NO2 sensor. Sensors and Actuators B: Chemical 1995, 25 (1-3), 388-391.

18. Mahajan, S.; Jagtap, S. Metal-oxide semiconductors for carbon monoxide (CO) gas sensing: A review. Applied Materials Today 2020, 18, 100483.

19. Phanichphant, S. Semiconductor metal oxides as hydrogen gas sensors. Procedia Engineering 2014, 87, 795-802.

20. Mirzaei, A.; Leonardi, S.; Neri, G. Detection of hazardous volatile organic compounds (VOCs) by metal oxide nanostructures-based gas sensors: A review. Ceramics International 2016, 42 (14), 15119-15141.

21. Barsan, N.; Weimar, U. Conduction model of metal oxide gas sensors. Journal of Electroceramics 2001, 7 (3), 143-167.

22. Bejaoui, A.; Guerin, J.; Zapien, J.; Aguir, K. Theoretical and experimental study of the response of CuO gas sensor under ozone. Sensors and Actuators B: Chemical 2014, 190, 8-15.

23. da Silva, L. F.; M’peko, J.-C.; Catto, A. C.; Bernardini, S.; Mastelaro, V. R.; Aguir, K.; Ribeiro, C.; Longo, E. UV-enhanced ozone gas sensing response of ZnO-SnO2 heterojunctions at room temperature. Sensors and Actuators B: Chemical 2017, 240, 573-579.

24. Martins, R.; Fortunato, E.; Nunes, P.; Ferreira, I.; Marques, A.; Bender, M.; Katsarakis, N.; Cimalla, V.; Kiriakidis, G. Zinc oxide as an ozone sensor. Journal of Applied Physics 2004, 96 (3), 1398-1408.

25. Soci, C.; Zhang, A.; Xiang, B.; Dayeh, S. A.; Aplin, D.; Park, J.; Bao, X.; Lo, Y.-H.; Wang, D. ZnO nanowire UV photodetectors with high internal gain. Nano Letters 2007, 7 (4), 1003-1009.

26. Fan, S.-W.; Srivastava, A. K.; Dravid, V. P. UV-activated room-temperature gas sensing mechanism of polycrystalline ZnO. Applied Physics Letters 2009, 95 (14), 142106.

27. Klingshirn, C. F.; Waag, A.; Hoffmann, A.; Geurts, J. Zinc oxide: from fundamental properties towards novel applications. 2010, 9-10.

28. Wang, Z. L. Zinc oxide nanostructures: growth, properties and applications. Journal of Physics: Condensed Matter 2004, 16 (25), R829.

29. Xu, S.; Wang, Z. L. One-dimensional ZnO nanostructures: solution growth and functional properties. Nano Research 2011, 4 (11), 1013-1098.

30. Baruah, S.; Dutta, J. Hydrothermal growth of ZnO nanostructures. Science and Technology of Advanced Materials 2009.

31. Schmidt-Mende, L.; MacManus-Driscoll, J. L. ZnO–nanostructures, defects, and devices. Materials Today 2007, 10 (5), 40-48.

32. Vempati, S.; Mitra, J.; Dawson, P. One-step synthesis of ZnO nanosheets: a blue-white fluorophore. Nanoscale Research Letters 2012, 7 (1), 1-10.

33. Azarov, A.; Rauwel, P.; Hallén, A.; Monakhov, E.; Svensson, B. G. Extended defects in ZnO: Efficient sinks for point defects. Applied Physics Letters 2017, 110 (2), 022103.

34. 陳伯証. 硫化鉬修飾氧化鋅奈米柱應用於室溫二氧化氮氣體感測. 碩士論文, 國立清華大學, 新竹市, 2021.

35. Ahn, M.-W.; Park, K.-S.; Heo, J.-H.; Park, J.-G.; Kim, D.-W.; Choi, K. J.; Lee, J.-H.; Hong, S.-H. Gas sensing properties of defect-controlled ZnO-nanowire gas sensor. Applied Physics Letters 2008, 93 (26), 263103.

36. Kumar, R. R.; Murugesan, T.; Chang, T.-W.; Lin, H.-N. Defect controlled adsorption/desorption kinetics of ZnO nanorods for UV-activated NO2 gas sensing at room temperature. Materials Letters 2021, 287, 129257.

37. Tian, H.; Fan, H.; Dong, G.; Ma, L.; Ma, J. NiO/ZnO p–n heterostructures and their gas sensing properties for reduced operating temperature. RSC Advances 2016, 6 (110), 109091-109098.

38. Fang, J.; Zhu, Y.; Wu, D.; Zhang, C.; Xu, S.; Xiong, D.; Yang, P.; Wang, L.; Chu, P. K. Gas sensing properties of NiO/SnO2 heterojunction thin film. Sensors and Actuators B: Chemical 2017, 252, 1163-1168.

39. Wang, Y.; Zhang, H.; Sun, X. Electrospun nanowebs of NiO/SnO2 pn heterojunctions for enhanced gas sensing. Applied Surface Science 2016, 389, 514-520.

40. Hong, L.-Y.; Ke, H.-W.; Tsai, C.-E.; Lin, H.-N. Low concentration NO gas sensing under ambient environment using Cu2O nanoparticle modified ZnO nanowires. Materials Letters 2016, 185, 243-246.

41. Bratsch, S. G. Standard electrode potentials and temperature coefficients in water at 298.15 K. Journal of Physical and Chemical Reference Data 1989, 18 (1), 1-21.

42. Fernando, C.; De Silva, P.; Wethasinha, S.; Dharmadasa, I.; Delsol, T.; Simmonds, M. Investigation of n-type Cu2O layers prepared by a low cost chemical method for use in photo-voltaic thin film solar cells. Renewable Energy 2002, 26 (4), 521-529.

43. Jung, S.; Jeon, S.; Yong, K. Fabrication and characterization of flower-like CuO–ZnO heterostructure nanowire arrays by photochemical deposition. Nanotechnology 2010, 22 (1), 015606.

44. Grätzel, M. Photoelectrochemical cells. In Materials For Sustainable Energy: A Collection of Peer-Reviewed Research and Review Articles from Nature Publishing Group, World Scientific, 2011; pp 26-32.

45. Arnold, D. W.; Xu, C.; Kim, E. H.; Neumark, D. M. Study of low‐lying electronic states of ozone by anion photoelectron spectroscopy of O− 3. The Journal of Chemical Physics 1994, 101 (2), 912-922.

46. Ervin, K. M.; Ho, J.; Lineberger, W. C. Ultraviolet photoelectron spectrum of nitrite anion. The Journal of Physical Chemistry 1988, 92 (19), 5405-5412.

47. 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, 25-42.

48. Gogurla, N.; Sinha, A. K.; Santra, S.; Manna, S.; Ray, S. K. Multifunctional Au-ZnO plasmonic nanostructures for enhanced UV photodetector and room temperature NO sensing devices. Scientific Reports 2014, 4 (1), 1-9.

49. Mhlongo, G. H.; Motaung, D. E.; Cummings, F.; Swart, H.; Ray, S. S. A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach. Scientific Reports 2019, 9 (1), 1-18.

50. Sahay, P.; Nath, R. Al-doped ZnO thin films as methanol sensors. Sensors and Actuators B: Chemical 2008, 134 (2), 654-659.

51. San, X.; Li, M.; Liu, D.; Wang, G.; Shen, Y.; Meng, D.; Meng, F. A facile one-step hydrothermal synthesis of NiO/ZnO heterojunction microflowers for the enhanced formaldehyde sensing properties. Journal of Alloys and Compounds 2018, 739, 260-269.

52. Belaqziz, M.; Amjoud, M. b.; Gaddari, A.; Rhouta, B.; Mezzane, D. Enhanced room temperature ozone response of SnO2 thin film sensor. Superlattices and Microstructures 2014, 71, 185-189.

53. Wu, R.-J.; Chiu, Y.-C.; Wu, C.-H.; Su, Y.-J. Application of Au/TiO2–WO3 material in visible light photoreductive ozone sensors. Thin Solid Films 2015, 574, 156-161.

54. da Silva, L. F.; Mastelaro, V. R.; Catto, A. C.; Escanhoela Jr, C. A.; Bernardini, S.; Zílio, S. C.; Longo, E.; Aguir, K. Ozone and nitrogen dioxide gas sensor based on a nanostructured SrTi0. 85Fe0. 15O3 thin film. Journal of Alloys and Compounds 2015, 638, 374-379.

55. Tsai, Y.-T.; Chang, S.-J.; Tang, I.-T.; Hsiao, Y.-J.; Ji, L.-W. High density novel porous ZnO nanosheets based on a microheater chip for ozone sensors. IEEE Sensors Journal 2018, 18 (13), 5559-5565.

56. Catto, A. C.; da Silva, L. F.; Ribeiro, C.; Bernardini, S.; Aguir, K.; Longo, E.; Mastelaro, V. R. An easy method of preparing ozone gas sensors based on ZnO nanorods. RSC Advances 2015, 5 (25), 19528-19533.

57. Sui, N.; Zhang, P.; Zhou, T.; Zhang, T. Selective ppb-level ozone gas sensor based on hierarchical branch-like In2O3 nanostructure. Sensors and Actuators B: Chemical 2021, 336, 129612.

58. Zhang, D.; Yang, Z.; Li, P.; Zhou, X. Ozone gas sensing properties of metal-organic frameworks-derived In2O3 hollow microtubes decorated with ZnO nanoparticles. Sensors and Actuators B: Chemical 2019, 301, 127081.