應用石墨烯於自供電超靈敏葡萄糖感測元件

Abstract

現今糖尿病患者所使用的血糖機是一種侵入式的量測方式，此方式不僅帶給病患許多的不便，也造成許多不必要的浪費。在本研究中，我們製造出以石墨烯/氧化鋅/P型矽基板的異質結構葡萄糖生物感測器，此感測器不同於以往依賴載子傳輸的物理性質變化，其特殊的工作原理是建立於氧化鋅的設計，因為氧化鋅能將載子牽制住不讓載子傳遞至下層的半導體，造就載子能夠最直接改變石墨烯的費米能階，造成整體能帶彎曲程度不同，間接改變跨於整體異質接面的輸出電流。藉由這樣的設計，此感測器的靈敏度極高，其可量測葡萄糖的範圍從0.1 pM到100 μM，如此廣泛的量測範圍比起現今已發表的論文都靈敏許多。另外，在此研究中，我們更運用室光激發此異質結構中的p-n接面來創造出自供電的葡萄糖生物感測器，其結果亦顯示出同樣的靈敏程度。因此，此異質結構葡萄糖生物感測器可被廣泛地運用於醫療，並有很大的機會能發展成被糖尿病患者使用的簡易且無痛血糖監測儀器。

A highly sensitive glucose biosensor based on graphene/ZnO/p-Si heterojunctions is demonstrated. Its sensing mechanism makes use of the large variation in the Fermi energy of graphene upon direct electron transfer of glucose oxidase at the presence of glucose molecules, with a film of ZnO acting as a sieve layer to block the carriers from transferring into the underlying semiconductor layer, resulting in a superb detection sensitivity. Through measurements of the current-voltage characteristics and time dependence of the changed current, this unique structure responds to glucose concentrations from as low as 0.1 pM to 100 μM range, which outperforms the best value ever reported by more than three orders of magnitude. Furthermore, we demonstrate the self-powered capability of this newly designed biosensor at room light illumination level, without compromising its sensitivity and dynamic range of detection. Altogether, this device presents with an excellent performance that surpasses all current glucose detection devices used in medical control, representing a novel possibility for easy and painless monitoring of blood glucose for patients with diabetes mellitus.