利用超快雷射製程製備石墨烯結構元件應用氣體偵測之研究

Abstract

本研究旨在利用超快雷射(Ultrafast laser)製程技術於石墨烯薄膜 (Graphene thin films)上製作電極與結構元件(Devices)，並將其應用於氣體偵測(Gas detection)，透過超快雷射製程成型薄膜表面與結構，進行製程參數的建置與分析，以利評估後續透過超快雷射製程於偵測元件的可行性。在超快雷射製程技術開發中，本研究採用超快雷射中波長為532 nm的皮秒雷射源(Picosecond laser source)，在較低的熱影響區(Low heat-affected zone)之製程機制條件下，以應用於薄膜結構元件上的製作。本研究利用超快雷射於石墨烯薄膜上製作間距2 mm的螺旋狀電極(Spiral electrode)與寬度和深度分別為22.43 m與12.48 m的指叉狀電極(Interdigitated electrode, IDE)元件，並且製作寬度和深度分別為25.81 m與15.24 m的微溝槽(Microgroove)結構元件。另一方面，本研究探討不同材料對氣體的偵測機制，包括石墨烯、氧化鋅奈米線(ZnO nanowires)以及還原氧化石墨烯(Reduced graphene oxide, rGO)；其中，利用螺旋狀電極搭配無線傳感模組(Wireless module)進行氣體偵測。此外，本研究會搭配水熱法(Hydrothermal method)和電紡絲法(Electrospinning method)的方式，在微溝槽與指叉狀電極上製作奈米線(或奈米纖維)，完成氣體偵測元件的研製。本研究結果顯示，利用超快雷射製程開發的氣體偵測元件，可實際應用在室溫下氣體偵測，包括偵測濃度5-150 ppm的一氧化碳(Carbon monoxide, CO)，以及偵測50-400 ppm的一氧化氮(Nitric oxide, NO)。

The purpose of this research was to use the ultrafast laser processing technique in fabricating the electrode and structure devices on graphene thin films for gas detection. The processing parameters can be established and analyzed in the ultrafast laser process where the formed surface and structure of thin films can be evaluated the feasibility for fabricating the detection devices. For the development of ultrafast laser technique, this work adopted the picosecond laser source with the wavelength of 532 nm, which can be generated the lower heat-affected zone for required patterning structures on thin film devices. In this study, the ultrafast laser is used to fabricate a spiral electrode with space of 2 mm, in which, the width and depth of interdigitated electrode were 22.43 m, and 12.48 m, respectively. Moreover, the formed width and depth of microgroove structure were 25.81m, and 15.24 m, respectively. On the other hand, this research investigated the mechanism of gas detection at the different materials, including graphene, ZnO nanowires and reduced graphene oxide (rGO). The spiral electrode was adapted with the wireless module for gas detection. In addition, the growth of nanowires (nanofibers) was formed on microgroove-structure and interdigitated-electrode devices by hydrothermal method and electrospinning method. The results demonstrated that the devices of gas detection under room temperature can fabricated by ultrafast laser process. The carbon monoxide (CO) and nitric oxide (NO) were detected at the concentration range of 50-150 ppm and 50-400 ppm, respectively.