Ambipolarity Sensitivity Investigation using a Charge-Plasma TFET with Graphene Channel for Biomolecule Detection

Abstract

This research proposes a label-free detection of neutral and charged biomolecules using a graphene channel-based charge-plasma tunnel field effect transistor (GC-CPTFET). The presence of a graphene channel provides a greater tunneling barrier at the channel/drain interface, significantly reducing ambipolarity and increasing the current gradient in the ambipolar condition. A nanocavity is created underneath the drain metal to investigate the sensitivity. Here, the various analog sensitivity parameters of the suggested biosensor are evaluated for a few neutral biomolecules in the ambipolar condition, including gelatin, biotin, and 3-aminopropyl-triethoxysilane (APTES). The sensor’s electrostatic performance, including its IDS-VGS characteristics, energy band, and tunneling distance, has been estimated in the ambipolar state. The sensitivity analysis is carried out in terms of ambipolar sensitivity (SAMB), transconductance (Sgm), cut-off frequency sensitivity (Sft), and maximum frequency sensitivity (Sfm). Further research has been done to study the effects of Deoxyribonucleic Acid (DNA), a charged biomolecule (k = 6) with varied positive and negative charge densities, on various sensitivity parameters. The detailed simulation work for the designed biosensor is achieved using the 2D Silvaco ATLAS device simulation tool.