Monolayer MoSe₂-Based Tunneling Field Effect Transistor for Ultrasensitive Strain Sensing

Abstract

This article presents a detailed investigation of the impact of mechanical strain on transition metal dichalcogenide (TMD) material-based tunneling field-effect transistor (TFET). First, the impact of mechanical strain on material parameters of MoSe2 is calculated using the first principle of density functional theory (DFT) under meta-generalized gradient approximation (MGGA). The device performance of the TMD TFET has been studied by solving the self-consistent 3-D Poisson and Schrodinger equations in nonequilibrium Green’s function (NEGF) framework. The results demonstrate that both ${I}_{\scriptscriptstyle {\rm {ON}}}$ and ${I}_{\scriptscriptstyle {\rm {OFF}}}$ increase with uniaxial tensile strain, however the change in ${I}_{\scriptscriptstyle {\rm {ON}}}/{I}_{\scriptscriptstyle {\rm {OFF}}}$ ratio remains small. This strain-dependent performance change in TMD TFET has been utilized to design an ultrasensitive strain sensor. The device shows a sensitivity ( $\Delta {I}_{\text {DS}}/{I}_{\text {DS}}$ ) of 3.61 for a strain of 2%. Due to the high sensitivity to the strain, these results show the potential of using MoSe2 TFET as a flexible strain sensor. Furthermore, the strained TFET is analyzed for backend circuit performance. It is observed that the speed and energy efficiency of ten-stage inverter chain based on controlled strain improve substantially in comparison to unstrained TFETs.