Graphene-FET for the detection of DNA translocation through a nanopore

Abstract

Nanopore is a highly promising platform for single molecule sensing and DNA sequencing. In the thesis, a new device combining nanopore structure with graphene field effect transistor (FET) is proposed as a single molecule DNA sensor. Recently, it has been reported that silicon nanowire FET fabricated on the nanopore membrane can detect local potential change arising from DNA translocation. Unlike silicon nanowire FET device, device using graphene FET can work even when ion concentrations of both chambers are identical and result in higher current change ratio. Besides, high charge carrier mobility of graphene allows fast operation of the device and higher chemical stability of graphene enables better durability in ionic solution. A numerical model is developed to expect the device performance and to prove superiority of the device to the previously reported one. The model is verified by comparing simulation result with experimental result reported recently. The model is also used for parametric study to establish the optimum design of the device. Effect of nanopore length, nanopore diameter, graphene channel length, graphene channel width, graphene doping level, and graphene mobility are examined and analyzed. Based on the optimized design, the graphene FET nanopore device is fabricated by using conventional top down processes and associated issues are discussed.