Tunnel FETs using Phosphorene/ReS 2 heterostructures

$2\mathrm{D}$ materials based heterostructures are potential candidates for Tunnel FETs (TFET) due to their self- passivated Van der Waals surfaces, which are ideally free from traps at the heterojunction interface [1]. In this study, we experimentally demonstrate heterostructure TFETs of ReS 2 and Phosphorene. $\mathrm{ReS}_{2}$ shows n-type behavior [2] and Phosphorene either an ambipolar or p-type behavior depending on the flake thickness and work function of contact metal [3]. The band alignment of Phosphorene- $\mathrm{ReS}_{2}$ heterostructure is either staggered or near broken gap configuration depending on the flake thickness [4]. Band-to-band tunneling (BTBT) and its signature Negative Differential Resistance (NDR) have been observed previously in $\mathrm{ReS}_{2}$ /Phosphorene heterostructures [5]. We show new insights on NDR and Negative Differential Transconductance (NDT) at different temperatures and their dependence on the thickness of ReS 2 and Phosphorene flakes and hence their doping concentration.