Fabrication and characterization of graphene field effect transistor for biosensor applications

Abstract

Graphene based sensor devices have been studied extensively and results of different chemicals decorated on a graphene sheet were detected by the transfer characteristics The present thesis was focused on the fabrication and characterizations of graphene field effect transistor and explored the ambipolar behavior of the device Based on the electrical property the graphene based devices were implemented in advanced applications namely DNA hybridization detection pH sensor and protein detection The GFET based device was fabricated by the mechanical exfoliation method with an inbuilt reference electrode acting as an electrolyte gate electrode Devices show good transfer characteristics which depend on the surface morphology of the material and substrate During fabrication of the device the substrate morphology was disturbed in appropriately by the contamination of the surface In the present study monolayer Graphene Field Effect Transistor GFET was driven with hydrophobic Hexamethyl Disilazane HMDS layer The HMDS layer was dehydrated prior and after the exfoliated monolayer graphene and the electrical characteristics were measured The transfer curve of the HMDS coated graphene device demonstrates superlative FET characteristics and prevents the contamination from the atmosphere under ambient conditions Fabrication of GFET device on the hydrophobic substrate enhances the effective ambipolar behavior newline