Material selection and device design guidelines for two-dimensional materials based TFETs

In this paper, we study the impact of different device architectures and material properties on the performance of two-dimensional tunnel FETs (2D TFETs). We show that single-gate (SG) device architecture in case of monolayer and few layers two-dimensional materials perform better than doublegate (DG) architecture. Due to sharper band bending at the tunneling junction, SG device offers shorter tunneling lengths resulting in larger ON currents. With physical insight into the device structure, we show that the gate-to-source outer fringing fields play a significant role in 2D TFETs performance. In order to reduce the effect of outer fringing fields, we propose a device structure with an interfacial layer (IL) between High-k and 2D material, resulting a 3-4x increase in ON current. Further, we show that ON currents can be further boosted by increasing the channel thickness. In the end, it is shown that a bi/tri-layer anisotropic 2D material based SG/DG TFET using IL can provide up to 400% higher ON current in comparison to monolayer 2D material based SG FET for equivalent effective mass and bandgap.