Graphene Nanoribbon-Based InSb/SiC TFETs with Nanogap-Enabled Tri-Metal Gate for Label-Free Biosensing Applications

In this work, an InSb/SiC-based tunnel field-effect transistor (TFET) with a tri-metal gate configuration and a graphene nanoribbon (GNR) channel for label-free biosensing applications is thoroughly analyzed. Asymmetric doping in the source, channel, and drain regions further increases device efficiency, and the heterojunction created between the InSb source and the SiC channel improves band-to-band tunneling. A dual-layer dielectric and a customized tri-metal gate stack are used to maximize sensor sensitivity and electrostatic control. A section of the gate dielectric is etched to form a nanogap cavity close to the source region, allowing for efficient biosensing. It is possible to inject both charged and neutral biomolecules into this cavity, which acts as the active detecting site. The effects of these biomolecules' varying charge densities and dielectric constants on device behavior are methodically investigated. Using TCAD simulations (Silvaco), device performance is assessed with an emphasis on critical factors such as band alignment, tunneling rate, electric field strength, surface potential, transconductance, and I-V characteristics. By tracking changes in peak drain current, transconductance, and the ON/OFF current ratio while target biomolecules are present, biosensor sensitivity is ascertained. The sensor’s dependability is further evaluated in real-world scenarios, such as partially filled nanocavities and molecular steric effects. The suggested GNR-based InSb/SiC TFET has enormous potential for sophisticated, high-sensitivity, label-free biosensing applications, according to the simulation results.