- 學位論文
利用濺鍍法沉積奈米金顆粒於三維發泡石墨烯表面並探討其在室溫下氨氣濃度感測之應用
Deposit gold nanoparticles on three-dimensional graphene foam via the sputter technique and analyze its application on ammonia gas sensing at room temperature
摘要
本研究製備一種奈米金顆粒/發泡石墨烯的結構並用於氨氣感測器的應用。以發泡鎳作為基板，用化學氣相沉積法成長石墨烯於其上，石墨烯的層數為5-10層，利用鹽酸蝕刻將鎳完全去除，即可得到一個三維網狀結構的發泡石墨烯。將其貼附於PET之上以穩固其結構作為基材，並利用濺鍍法將奈米金顆粒沉積於石墨烯表面以進行改質，在本實驗中，亦利用不同的濺鍍參數控制奈米金顆粒的大小。 結果顯示，藉由將奈米金沉積於發泡石墨烯上可明顯增加其在氨氣感測方面的敏感度、響應時間、回復時間等性質。而其感測表現亦隨著沉積奈米金顆粒的大小不同而改變，由於小顆粒之奈米金可以使發泡石墨烯之比表面積大幅度增加，因此其感測表現較大顆粒之奈米金更佳，此外此元件製備簡單可於室溫下對ppm等級濃度氨氣具有高敏感度並具有可逆性。 本研究亦探討不同溫度下此元件對氨氣感測的能力，於高溫環境下元件對氨氣的吸附及脫附能力有明顯的提升，可利用升溫的方式使氣體完全的脫附。
並列摘要
This study used a gold-nanoparticle-decorated graphene foam composite as a sensor for detecting low concentration ammonia gas. Few-layer graphene was grown on the nickel foam by CVD. Then the nickel foam was removed by a etching process to fabricate a three-dimensional graphene foam structure. Graphene foam was then adhered to a PET film to prevent the graphene foam structure from collapse during handling. Gold nanoparticles with different sizes were deposited on the surface of the graphene foam by sputtering. The results showed that the sensitivity, recovery time, and response time of the sensor were enhanced attributing to the deposition of gold nanoparticles on the surface of graphene foam. Size effects of gold nanoparticles on the performance of the sensor were studied and it was found that smaller gold nanoparticles enhance the sensitivity of the device significantly due to the increase of the specific surface area. In addition, the sensor possessing high sensitivity in the range of 50 to 1000 ppm for NH3 and having reversible behavior were detected. The dependence of the sensing ability in the operating temperature was also investigated. In high operating temperature, the ability of adsorption and desorption of the ammonia molecules was remarkable enhanced owing to the fully desorption of the NH3 at elevated temperature.