Fabrication of few-layer graphene film based field effect transistor and its application for trace-detection of herbicide atrazine
Thi Thanh Cao, Van Chuc Nguyen, Hai Binh Nguyen, Hung Thang Bui, Thi Thu Vu, Ngoc Hong Phan, Bach Thang Phan, Le Hoang, Maxime Bayle, Matthieu Paillet, Jean Louis Sauvajol, Ngoc Minh Phan and Dai Lam Tran
Abstract
We describe the fabrication of highly sensitive graphene-based field effect transistor (FET) enzymatic biosensor for trace-detection of atrazine. The few-layers graphene films were prepared on polycrystalline copper foils by atmospheric pressure chemical vapor deposition method using an argon/hydrogen/methane mixture. The characteristics of graphene films were investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results indicated low uniformity of graphene layers, which is probably induced by heterogeneous distribution of graphene nucleation sites on the Cu surface. The pesticide detection is accomplished through the measurement of the drain-source current variations of the FET sensor upon the urea enzymatic hydrolysis reaction. The obtained biosensor is able to detect atrazine with a sensitivity of 56 μA/logCATZ in range between 2 × 10−4 and 20 ppb and has a limit of detection as low as 0.05 ppt. The elaboration of such highly sensitive biosensors will provide better biosensing performances for the detection of biochemical targets
