Attomolar Sensitivity of FET Biosensor Based on Smooth and Reliable Graphene Nanogrids

A smooth and reliable reduced graphene oxide (RGO) nanogrid structure has been developed using a nanoporous silicon oxide template, which resulted in the attomolar sensitivity of a field effect transistor biosensor. Scanning electron microscopy, Raman, surface profilometry, and conductance measurements verify the nanogrid structure of RGO, its bilayer thickness, and smoothness. The conductance of the biosensor reliably increases with the increasing concentration of hepatitis B virus molecules. The combined effects of insignificant line edges, quantum dot like transport behaviors, and improved interaction of the biomolecules within the nanopores with the pore walls have been attributed to the ultrasensitivity of the biosensor.