飛秒雷射製作可撓性聚醯亞胺異質結構元件於氣體檢測之研究

Abstract

本研究是利用超快飛秒雷射(Ultrafast femtosecond laser)之超短脈衝(Ultrashortpulses)的特性，在聚醯亞胺(Polyimide, PI)薄膜基材，製作指叉狀電極結構(Interdigitated electrode structures)元件於氣體檢測(Gas detection)，該超快雷射製程具較小熱影響區(Heat-affected zone)，以能進行可撓性基材之結構製作。為增加此元件感測之靈敏度，本研究亦利用水熱法製成氧化鋅(Zinc oxide)奈米線結構(Nanowires)，在飛秒雷射製程製作之石墨烯PI電極元件上，以成型新穎複合結構元件於氣體檢測，以增加感測響應值。本研究顯示該可撓性元件可避免受力而導致斷裂、破壞的現象，且當彎曲曲率半徑小於6 mm響應值仍屬穩定(誤差值±3%)。元件設計的微型加熱器方面顯示，在一氧化碳(Carbon monoxide, CO)氣體從室溫到85.6°C可縮短恢復時間為86.2sec；甲烷(Methane, CH4)氣體則從室溫到約86.8°C可縮短恢復時間為117.2 sec。因此，在氣體感測元件方面顯示，一氧化碳和甲烷氣體檢測於200濃度200 ppm，其元件在甲烷與一氧化碳氣之電性響應值會分別為20.7 %和120.8 %。藉此，本研究證明氧化鋅/石墨烯可撓性微性加熱元件於一氧化碳和甲烷氣體濃度具有良好的恢復性，分別在1000 sec和1600 sec可恢復至初始電阻值，且該元件靈敏度則在加熱升溫環境會別為0.6728與0.0434為最佳。透過此研究，將可提供飛秒雷射製程於氣體檢測元件之應用參考。

關鍵詞: 飛秒雷射、可撓性元件、石墨烯、奈米線、氣體檢測

In this study, the characteristics of femtosecond laser with the ultrashort pulseswere used to fabricate the graphene-based interdigitated electrode structures onthe polyimide (PI) film substrate for gas detection. The design of flexible devicesutilizing the ultrafast laser process was the low power consumption and small heat-affected zone. To enhance the sensing sensitivity of formed device, this study canbe used the hydrothermal method to fabricate zinc oxide nanowires on the laser-ablated graphene electrode devices on the surface of PI substrate. The flexibledevices with the composite materials and nano- and micro-structures were formedfor gas detection, so as to the sensing response was increased. This study showedthat the flexible device can effectively avoid the force to cause the phenomenon offracture and damage. And the measured response was stable when the bendingradius of curvature is less than 6 mm (the error value ~ ±3%). For the designeddevice with the microheater for the gas detection, it indicated that the carbonmonoxide (CO) gas can shorten the recovery time by 86.2 sec from roomtemperature to 85.6°C. And the sensing device for detection of methane (CH4)gas can shorten the recovery time by 117.2 sec from room temperature to 86.8 °C.In terms of fabricated device for gas detection at the concentration of 200 ppm,the electrical response of CO and CH4 gas can be 20.7% and 120.8%, respectively.By this way, this study proved that the zinc oxide and graphene-based flexibledevice with the heater was the good recovery performance for the detection ofCO and CH4, where the initial resistance values can be recovered at 1000 sec and1600 sec, respectively. Additionally, the sensitivity of device for the CO and CH4gas in heating environment were 0.6728, and 0.0434, respectively. Through thisresearch, it will offer to the application of femtosecond laser technique in gassensing device as a reference.Keywords: Femtosecond laser, Flexible device, Graphene, Nanowires, Gas detection