本研究以水溶液法分別在濺鍍氧化鋅(ZnO)與氧化鋅摻雜鋁(AZO)晶種層之可撓性基板PDMS上合成一維氧化鋅奈米柱陣列，探討氧化鋅成長結構與特性分析，並將其製作為可撓式複合功能壓阻式觸覺感測器。本研究以硝酸鋅六水合物(Zinc nitrate hexahydrate)與六亞甲基四胺 (HTMA) 濃度 1 : 1， 在ZnO 晶種層反應溫度為 95°C 與 AZO 晶種層 90°C，反應時間 10 小時下，合成出高品質與高深寬比之一維氧化鋅奈米柱陣列，且分別利用 X 光射線粉末繞射分析儀、場發射掃描式電子顯微鏡、能量散射光譜儀，分析與探討 ZnO 奈米柱結晶、微結構、品質特性。將兩片成長一維氧化鋅奈米柱陣列之可撓性 PDMS 基板相互組裝，使上、下兩片ZnO奈米柱陣列形成仿生交互鏈鎖結構，藉由施加壓力使奈米柱間之接觸電阻產生改變，以壓阻的方式作為觸覺感測機制，分別量測與探討靜態及動態之施加壓力，另外本研究也利用 ZnO 材料之半導體熱阻效應感測環境溫度，製作可撓式複合功能觸覺感測器，期能應用於人工電子皮膚、人工義肢、穿戴式裝置等領域上。

關鍵字: ZnO奈米柱、可撓式複合功能觸覺感測器、水溶液法

In this study, the flexible PDMS substrates are coated with zinc oxide and zinc oxide doped with aluminum films respectively as seed layers. And the aqueous solution method is used to synthesize one-dimensional zinc oxide nanorods. Then, the PDMS substrates with zinc oxide nanorods are combined to make a multifunctional piezoresistive tactile sensors for artificial electronic skins. The growth solution with aqueous solution method are mixed by dissolving the zinc nitrated and hexamethylenetetramine in the deionized water in a 1:1 ratio. The reaction temperature of solution is 95 degrees for zinc oxide seed layers and 90 degrees for zinc oxide doped with aluminum seed layers, and the reaction time of solution is 10 hours. Then successfully synthesized the high quality and high aspect ratio one-dimensional zinc oxide nanorods on PDMS substrates. Crystal structure and growth morphology of zinc oxide nanorods were investigated by X-ray power diffractometer and field emission scanning electron microscopy respectively, and energy-dispersive X-ray spectroscopy was used to analyze the composition of Zinc oxide nanorods. The two PDMS substrates with zinc oxide nanorod arrays as the upper and lower electrode were combined each other to form interlocked structure by zinc oxide nanorods. In this interlocked geometry, an applied pressure induces a change in the contact area between interlocked zinc oxide nanorods, thus changing the contact resistance. In addition, the semiconductor thermal properties of zinc oxide can be applied to detect environmental temperature. The flexible multifunctional tactile sensor may find applications such as artificial electronic skins, artificial prosthetics, and wearable devices.

[1] Z. Chu, P. M. Sarro, and S. Middelhoek, "Silicon three-axial tactile sensor," Sensors and Actuators A: Physical, vol. 54, pp. 505-510, 1996.
[2] W. H. Ko and Q. Wang, "Touch mode capacitive pressure sensors," Sensors and Actuators A: Physical, vol. 75, pp. 242-251, 1999.
[3] B. J. Kane, M. R. Cutkosky, and G. T. A. Kovacs, "A traction stress sensor array for use in high-resolution robotic tactile imaging," Journal of Microelectromechanical Systems, vol. 9, pp. 425-434, 2000.
[4] M. Ádám, T. Mohácsy, P. Jónás, C. Dücső, É. Vázsonyi, and I. Bársony, "CMOS integrated tactile sensor array by porous Si bulk micromachining," Sensors and Actuators A: Physical, vol. 142, pp. 192-195, 2008.
[5] H. K. Lee, S. I. Chang, and E. Yoon, "A Flexible Polymer Tactile Sensor: Fabrication and Modular Expandability for Large Area Deployment," Journal of Microelectromechanical Systems, vol. 15, pp. 1681-1686, 2006.
[6] W. Y. Chang, T. H. Fang, H. J. Lin, Y. T. shen, and Y. C. Lin, "A Large Area Flexible Array Sensors Using Screen Printing Technology," Journal of Display Technology, vol. 5, pp. 178-183, 2009.
[7] S. Gong, W. Schwalb, Y. Wang, Y. Chen, Y. Tang, J. Si, et al., "A wearable and highly sensitive pressure sensor with ultrathin gold nanowires," Nat Commun, vol. 5, 2014.
[8] M. Ha, S. Lim, J. Park, D. S. Um, Y. Lee, and H. Ko, "Bioinspired Interlocked and Hierarchical Design of ZnO Nanowire Arrays for Static and Dynamic Pressure-Sensitive Electronic Skins," Advanced Functional Materials, vol. 25, pp. 2841-2849, 2015.
[9] 王詠辰, "可檢測正向力和剪力之透明軟性觸覺感測器系統," 國
立清華大學動力機械工程學系碩士論文, 民國一百零五年七月.
[10] C. Pang, G. Y. Lee, T. Kim, S. M. Kim, H. N. Kim, S. H. Ahn, et al., "A flexible and highly sensitive strain-gauge sensor using reversible interlocking of nanofibres," Nature Materials, vol. 11, pp. 795-801, 2012.
[11] J. Park, Y. Lee, J. Hong, Y. Lee, M. Ha, Y. Jung, et al., "Tactile-Direction-Sensitive and Stretchable Electronic Skins Based on Human-Skin-Inspired Interlocked Microstructures," ACS Nano, vol. 8, pp. 12020-12029, 2014.
[12] Y. Jung, D. G. Lee, J. Park, H. Ko, and H. Lim, "Piezoresistive Tactile Sensor Discriminating Multidirectional Forces," Sensors, vol. 15, pp. 25463-25473, 2015.
[13] Y. J. Yang, M. Y. Cheng, W. Y. Chang, L. C. Tsao, S. A. Yang, W. P. Shih, et al., "An integrated flexible temperature and tactile sensing array using PI-copper films," Sensors and Actuators A: Physical, vol. 143, pp. 143-153, 2008.
[14] J. S. Lee, K. Y. Shin, O. J. Cheong, J. H. Kim, and J. Jang, "Highly Sensitive and Multifunctional Tactile Sensor Using Free-standing ZnO/PVDF Thin Film with Graphene Electrodes for Pressure and Temperature Monitoring," Scientific Reports, vol. 5, pp. 7887, 2015.
[15] Z. Fu, B. Lin, and J. Zu, "Photoluminescence and structure of ZnO films deposited on Si substrates by metal-organic chemical vapor deposition," Thin Solid Films, vol. 402, pp. 302-306, 2002.
[16] J. Ye, S. Gu, S. Zhu, T. Chen, L. Hu, F. Qin, et al., "The growth and annealing of single crystalline ZnO films by low-pressure MOCVD," Journal of Crystal Growth, vol. 243, pp. 151-156, 2002.
[17] K. H. Yoon and J. Y. Cho, "Photoluminescence characteristics of zinc oxide thin films prepared by spray pyrolysis technique," Materials Research Bulletin, vol. 35, pp. 39-46, 2000.
[18] Y. G. Wang, S. P. Lau, X. H. Zhang, H. W. Lee, S. F. Yu, B. K. Tay, et al., "Evolution of visible luminescence in ZnO by thermal oxidation of zinc films," Chemical Physics Letters, vol. 375, pp. 113-118, 2003.
[19] W. Water and S. Y. Chu, "Physical and structural properties of ZnO sputtered films," Materials Letters, vol. 55, pp. 67-72, 2002.
[20] Y. Nakanishi, A. Miyake, H. Kominami, T. Aoki, Y. Hatanaka, and G. Shimaoka, "Preparation of ZnO thin films for high-resolution field emission display by electron beam evaporation," Applied Surface Science, vol. 142, pp. 233-236, 1999.
[21] L. Duan, X. Zhao, Y. Zhang, H. Shen, and R. Liu, "Fabrication of flexible Al-doped ZnO films via sol–gel method," Materials Letters, vol. 162, pp. 199-202, 2016.
[22] N. H. Alvi, W. u. Hassan, B. Farooq, O. Nur, and M. Willander, "Influence of different growth environments on the luminescence properties of ZnO nanorods grown by the vapor–liquid–solid (VLS) method," Materials Letters, vol. 106, pp. 158-163, 2013.
[23] Y. C. Yoon, K. S. Park, and S. D. Kim, "Effects of low preheating temperature for ZnO seed layer deposited by sol–gel spin coating on the structural properties of hydrothermal ZnO nanorods," Thin Solid Films, vol. 597, pp. 125-130, 2015.
[24] L. Vayssieres, "Growth of Arrayed Nanorods and Nanowires of ZnO from Aqueous Solutions," Advanced Materials, vol. 15, pp. 464-466, 2003.
[25] S. N. Das, J. P. Kar, J. H. Choi, T. I. Lee, K. J. Moon, and J. M. Myoung, "Fabrication and Characterization of ZnO Single Nanowire-Based Hydrogen Sensor," The Journal of Physical Chemistry C, vol. 114, pp. 1689-1693, 2010.
[26] S. Stassi, G. Canavese, F. Cosiansi, R. Gazia, and M. Cocuzza, "A Tactile Sensor Device Exploiting the Tunable Sensitivity of Copper-PDMS Piezoresistive Composite," Procedia Engineering, vol. 47, pp. 659-663, 2012.
[27] N. Thanh-Vinh, N. Binh-Khiem, H. Takahashi, K. Matsumoto, and I. Shimoyama, "High-sensitivity triaxial tactile sensor with elastic microstructures pressing on piezoresistive cantilevers," Sensors and Actuators A: Physical, vol. 215, pp. 167-175, 2014.
[28] H. B. Muhammad, C. Recchiuto, C. M. Oddo, L. Beccai, C. J. Anthony, M. J. Adams, et al., "A capacitive tactile sensor array for surface texture discrimination," Microelectronic Engineering, vol. 88, pp. 1811-1813, 2011.
[29] M. I. Tiwana, A. Shashank, S. J. Redmond, and N. H. Lovell, "Characterization of a capacitive tactile shear sensor for application in robotic and upper limb prostheses," Sensors and Actuators A: Physical, vol. 165, pp. 164-172, 2011.
[30] L. Seminara, M. Capurro, P. Cirillo, G. Cannata, and M. Valle, "Electromechanical characterization of piezoelectric PVDF polymer films for tactile sensors in robotics applications," Sensors and Actuators A: Physical, vol. 169, pp. 49-58, 2011.
[31] M. S. Kim, H. R. Ahn, S. Lee, C. Kim, and Y. J. Kim, "A dome-shaped piezoelectric tactile sensor arrays fabricated by an air inflation technique," Sensors and Actuators A: Physical, vol. 212, pp. 151-158, 2014.
[32] Y. Yang, H. Zhang, Z. H. Lin, Y. S. Zhou, Q. Jing, Y. Su, et al., "Human Skin Based Triboelectric Nanogenerators for Harvesting Biomechanical Energy and as Self-Powered Active Tactile Sensor System," ACS Nano, vol. 7, pp. 9213-9222, 2013.
[33] H. Kotani, M. Takasaki, T. Mizuno, and T. Nara, "Integration of Tactile Information and Visual Information Using A Glass Substrate Surface Acoustic Wave Tactile Display," SICE-ICASE, 2006. International Joint Conference, pp. 5411-5414, 2006.
[34] Z. L.Wang, "Nanogenerators for self-powered devices and systems," 2011.
[35] S. J. Pearton, D. P. Norton, K. Ip, Y. W. Heo, and T. Steiner, "Recent progress in processing and properties of ZnO," Superlattices and Microstructures, vol. 34, pp. 3-32, 2003.
[36] M. Chen, Z. L. Pei, X. Wang, C. Sun, and L. S. Wen, "Structural, electrical, and optical properties of transparent conductive oxide ZnO:Al films prepared by dc magnetron reactive sputtering," Journal of Vacuum Science & Technology A, vol. 19, pp. 963-970, 2001.
[37] J. Kobmann and C. Hattig, "Investigation of interstitial hydrogen and related defects in ZnO," Physical Chemistry Chemical Physics, vol. 14, pp. 16392-16399, 2012.
[38] J. F. Shackelford, Introduction to Materials Science for Engineers, 8th edition, Pearson, 2015 .
[39] R. Srivastava, "Investigation on Temperature Sensing of Nanostructured Zinc Oxide Synthesized via Oxalate Route," Journal of Sensor Technology, vol. 02, pp. 8-12, 2012.
[40] H. Wang, J. Xie, K. Yan, and M. Duan, "Growth Mechanism of Different Morphologies of ZnO Crystals Prepared by Hydrothermal Method," Journal of Materials Science & Technology, vol. 27, pp. 153-158, 2011.
[41] W. Y. Chang, T. H. Fang, and J. H. Tsai, "Electromechanical and Photoluminescence Properties of Al-doped ZnO Nanorods Applied in Piezoelectric Nanogenerators," Journal of Low Temperature Physics, vol. 178, pp. 174-187, 2014.
[42] S. H. Yi, S. K. Choi, J. M. Jang, J. A. Kim, and W. G. Jung, "Patterned Growth of a Vertically Aligned Zinc Oxide Rod Array on a Gallium Nitride Epitaxial Layer by Using a Hydrothermal Process," Korean Physical Society, vol. 53, pp. 227-231, 2008.

[43] C. T. Pan, Y. C. Chen, C. C. Hsieh, C. H. Lin, C. Y. Su, C. K. Yen, et al., "Ultrasonic sensing device with ZnO piezoelectric nanorods by selectively electrospraying method," Sensors and Actuators A: Physical, vol. 216, pp. 318-327, 2014.