本研究利用皮秒雷射直寫(Picosecond laser direct-writing)技術於石墨烯薄膜(Graphene film )上，進行可撓性導電元件(Flexible conductive device)之製作，該元件設計是包含微加熱器(Micro-heater)與微感測器(Micro-sensor)之兩種電極結構。透過電極結構不同間距(Gap)的設計，探討微加熱器之熱電學特性，以及對於微感測器之靈敏度影響。進一步，本研究利用彎曲(Bending)實驗在可撓性導電元件進行穩定性測試。實驗結果顯示，當輸入電壓12 V時，微加熱器能夠於10 sec內快速提升至穩態溫度，其最高溫度可以達到85 °C，以及具有均勻熱分佈之效果。進一步，當微加熱器之電阻值分別控制為206.90±6.21 Ω及290.25±8.71 Ω時，在輸入電壓12 V下分別能夠達到90.54±6.06 °C與53.55±3.85 °C，說明了製備較低電阻值之微加熱器能夠得到更佳的升溫特性。此外，利用微加熱器作為熱源，能夠使微感測器的電阻產生變化，藉此獲得溫度感測器調控之驗證。實驗結果顯示，當改變間距從1300 μm 至100 μm時，其元件靈敏度值自3.35×10-4 °C-1提高至14.7×10-4 °C-1，大幅增加了77.21 %，證明當兩電極的間距愈接近時，其靈敏度會增加。最後，本研究進行可撓性導電元件之彎曲次數100次循環下，該元件電阻與溫度性質不受影響，其誤差值分別在±5 %與±5 °C，說明此研究開發之石墨烯導電薄膜元件，具有良好的抗彎折特性，以應用於可撓性導電元件之溫度感測。

In this study, a picosecond laser direct-writing technique was used to fabricate flexible conductive device on the graphene film. The device design included two types of electrode structures that were micro-heater and micro-sensor. Through the design of the gap at the different electrode structures, the thermoelectric characteristics of the micro-heater and the sensitivity effect on the micro-sensor were discussed. The experimental results revealed that the micro-heater can rise rapidly to a steady-state temperature (stability) within 10 sec when the input voltage was 12 V. Here, a maximum temperature of 85 °C and a uniform heat distribution can be shown. When the resistance value of micro-heater was controlled to 206.90±6.21 Ω and 290.25±8.71 Ω, respectively, the temperature can reach 90.54±6.06 °C and 53.55±3.85 °C at the input voltage of 12 V. It indicated that the micro-heater can obtain better temperature rise characteristics. In addition, by using the micro-heater as a heat source, the resistance of the micro-sensor can be changed, thereby gaining verification of feedback from a controller with temperature sensor. When the gap distance is changed from 1300 μm to 100 μm, the sensitivity can be increased from 3.35×10-4 °C-1 to 14.7×10-4 °C-1. It shown the sensitivity increased by 77.21 %, which can prove that the sensitivity of the two electrodes was increased as the distance between the two electrodes was closer. Finally, the resistance and temperature characteristics of flexible conductive device can maintain stability after bending the device in 100 cycles, in which the error values are ±5 % and ±5 °C, respectively. Based on this work, the study of the graphene-based conductive thin-film device has the good characteristics of flexible test, verifying the application to temperature sensing of flexible conductive device.

[1] 錫安市場研究，”全球溫度感測器市場現況”.2018.
[2] T. Pan, W. Cao, and M. Wang, “TiO2 thin film temperature sensor monitored by smartphone,” Optical fiber technology., vol. 45, pp. 359–362, 2018.
[3] Y. Jin, E. P. Boon, L. T. Le, W. Lee, “Fabric-infused array of reduced graphene oxide sensors for mapping of skin temperatures,” Sensors actuators a physical., vol. 280, pp. 92–98, 2018.
[4] H. Song, J. Kim, B. S. Kim, J. Koo, “Development of a food temperature prediction model for real time food quality assessment,” International journal of refrigeration., vol. 98, pp. 468–479, 2019.
[5] N. Kurra, Q. Jiang, P. Nayak, H. N. Alshareef, “Laser-derived graphene: a three-dimensional printed graphene electrode and its emerging applications,” Nano today, vol. 24, pp. 81–102, 2019.
[6] S. U. S. Choi, J. A. Eastman, “Enhancing thermal conductivity of fluids with nanoparticles,”ASME international mechanical engineering congress and exposition, vol. 66, pp. 99–105, 1995.
[7] S. Hong, H Lee, J Lee, “Highly stretchable and transparent metal nanowire heater for wearable electronics applications,” Advanced materials., vol. 27, pp. 4744–4751, 2015.
[8] C. Li, Y. T. Xu, B. Zhao, L. Jiang, S. G. Chen, J. B. Xu, "Flexible graphene electrothermal films made from electrochemically exfoliated graphite," Journal of materials science, vol. 51, pp. 1043-1051, 2016.
[9] K. D. M. Rao, G. U. Kulkarni, “A highly crystalline single Au wire network as a high temperature transparent heater,” Nanoscale, vol. 6, p. 5645, 2014.
[10] D. Sui, Y. Huang, L. Huang, J. Liang, Y. Ma, Y. Chen, “Flexible and transparent electrothermal film heaters based on graphene materials,” Small, vol. 7, pp. 3186–3192, Nov. 2011.
[11] J. J. Bae, S. C. Lim, G. H. Han, Y. W. Jo, D. L. Doung, E. S. Kim, "Heat dissipation of transparent graphene defoggers," Advanced functional materials, vol. 22, pp. 4819-4826, 2012.
[12] 雷射產業新聞，”雷射應用之市場分析”, 2015.
[13] 雷射焊接LBW的優勢，source :https://kknews.cc/science/m2ymze9.html , retrieved 2017.
[14] Machining with long pulse lasers, machining with ultrafast laser pulses, source: http://www.cmxr.com/ Education/Long.html, retrieved 2016.
[15] 超快雷射加工，source : https://kknews.cc/zh-tw/news/bxzkp36.html , retrieved 2017.
[16] V. Kohlschütter, P. Haenni, “Zur Kenntnis des Graphitischen Kohlenstoffs und der Graphitsäure,” Zeitschrift für Anorg. und Allg. Chemie, vol. 105, no. 1, pp. 121–144, Jan. 1919.
[17] G. Ruess, F. Vogt, “Höchstlamellarer kohlenstoff aus Graphitoxyhydroxyd.,” Monatshefte für chemie, vol. 78, pp. 222–242, 1948.
[18] A. K. Geim, K. S. Novoselov, "The rise of graphene," Nature materials, vol. 6, pp. 183-191, 2007.
[19] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, "Electric field in atomically thin carbon films," Science, vol. 306, pp. 666-669, 2004.
[20] R. R. Nair, P. Blake, A. N. Grigorenko, K. S. Novoselov, T. J. Booth, T. Stauber, "Fine structure constant defines visual transparency of graphene," Science, vol. 320, pp. 1308-1308, 2008.
[21] A. A. Balandin, S. Ghosh, W. Bao, I. Calizo, D. Teweldebrhan, F. Miao, "Superior thermal conductivity of single-layer graphene," Nano letters, vol. 8, pp. 902-907, 2008.
[22] K. I. Bolotin, K. J. Sikes, Z. Jiang, M. Klima, G. Fudenberg, J. Hone, "Ultrahigh electron mobility in suspended graphene," Solid state communications, vol. 146, pp. 351-355, 2008.
[23] C. Lee, X. Wei, J. W. Kysar, J. Hone, "Measurement of the elastic properties and intrinsic strength of monolayer graphene," Science, vol. 321, pp. 385-388, 2008.
[24] Article library,
source:https://www.digikey.tw/zh/articles/techzone/
2011/oct/temperature-sensors-the-basics, retrieved 2011,
[25] Environmental control, OF week, source : https://mp.ofweek.com/ecep/a445673627666, retrieved 2019.
[26] Household appliances, source :
http://big5.sj33.cn/sc/slsc/ryp/
201410/40408.html, retrieved 2014.
[27] Food processing, source : https://www.secretchina.com/
news/b5/2017/03/27/818101.html retrieved 2017.
[28] Smart measurement, source : https://www.smartmeasurement.com/
[29] KITS & SOLUTIONS ,source : https://www.efxkits.us/different-types-temperature-sensor-applications/,
[30] M. Lim, H. J. Kim, E. H. Ko, J. Choi, H. K. Kim, "Ultrafast laser-assisted selective removal of self-assembled Ag network electrodes for flexible and transparent film heaters," Journal of alloys and compounds, vol. 688, pp. 198-205, 2016.
[31] S. Xu, L. Ren, B. Liu, J. Wang, B. Tang, W. Zhou, "Single-step selective metallization on insulating substrates by laser-induced molten transfer," Applied Surface Science, vol. 454, pp. 16-22, 2018.
[32] S. Y. Lin, T. Y. Zhang, Q. Lu, D. Y. Wang, Y. Yang, X. M. Wu, "High-performance graphene-based flexible heater for wearable applications," RSC Advances, vol. 7, pp. 27001-27006, 2017.
[33] S. Mortazavi, M. Mollabashi, S. I. Shah, "Micropatterning of CVD single layer graphene using KrF laser irradiation," Applied surface science, vol. 428, pp. 94-97, 2018.
[34] M. Kasischke, E. Subaşı, C. Bock, D.-V. Pham, E. L. Gurevich, U. Kunze, et al., "Femtosecond laser patterning of graphene electrodes for thin-film transistors," Applied surface science, vol. 478, pp. 299-303, 2019.
[35] K. C. Ke, C. Cheng, L. J. Lin, S. Y. Yang, "A novel flexible heating element using graphene polymeric composite ink on polyimide film," Microsystem technologies, vol. 24, pp. 3283-3289, 2018.
[36] C. Salvo, R. V. Mangalaraja, R. Udayabashkar, M. Lopez, C. Aguilar, "Enhanced mechanical and electrical properties of novel graphene reinforced copper matrix composites," Journal of alloys and compounds, vol. 777, pp. 309-316, 2019.
[37] B. Davaji, H. D. Cho, M. Malakoutian, J. K. Lee, G. Panin, T. W. Kang, "A patterned single layer graphene resistance temperature sensor," Scientific reports, vol. 7, pp. 8811, 2017.
[38] R. Pawlak, M. Lebioda, "Electrical and thermal properties of heater-sensor microsystems patterned in TCO films for wide-range temperature applications from 15 K to 350 K," Sensors, vol. 18, p. 1831, 2018.
[39] P. H. Wang, S. P. Chen, C. H. Su, and Y. C. Liao, "Direct printed silver nanowire thin film patterns for flexible transparent heaters with temperature gradients," RSC advances, vol. 5, pp. 98412-98418, 2015.
[40] K. H. Pyo and J. W. Kim, "Transparent and mechanically robust flexible heater based on compositing of Ag nanowires and conductive polymer," Composites science and technology, vol. 133, pp. 7-14, 2016.
[41] T. Y. Zhang, H. M. Zhao, D. Y. Wang, Q. Wang, Y. Pang, N.-Q. Deng, "A super flexible and custom-shaped graphene heater," Nanoscale, vol. 9, pp. 14357-14363, 2017.
[42] M. Tian, Y. Hao, L. Qu, S. Zhu, X. Zhang, S. Chen, "Enhanced electrothermal efficiency of flexible graphene fabric Joule heaters with the aid of graphene oxide," Materials letters, vol. 234, pp. 101-104, 2019.
[43] M. R. Bobinger, F. J. Romero, A. Salinas-Castillo, M. Becherer, P. Lugli, D. P. Morales, "Flexible and robust laser-induced graphene heaters photothermally scribed on bare polyimide substrates," Carbon, vol. 144, pp. 116-126, 2019.
[44] A. Scorzoni, D. Caputo, G. Petrucci, P. Placidi, S. Zampolli, G. De Cesare, "Design and experimental characterization of thin film heaters on glass substrate for Lab-on-chip applications," Sensors and Actuators, A: Physical, vol. 229, pp. 203-210, 2015.
[45] S. Yu, S. Wang, M. Lu, L. Zuo, "A novel polyimide based micro heater with high temperature uniformity," Sensors and Actuators, A: Physical, vol. 257, pp. 58-64, 2017.
[46] W. Xu, T. Yang, F. Qin, D. Gong, Y. Du, G. Dai, "A Sprayed graphene pattern-based flexible strain sensor with high sensitivity and fast response," Sensors, vol. 19, p. 1077, 2019