Cold source FET with 2D TMDs type III band aligned heterojunctions

Cold source filed-effect-transistor (CSFET) is a FET system with Sub-60 mV/dec subthreshold swing, achieved by introducing a bandgap at the FET source that cuts down thermal carriers in the off-state. In this work, CSFET with two-dimensional (2D) type-III band aligned WTe₂/HfS₂ heterojunction is investigated by using first-principles quantum transport simulations. Different from previous CSFETs based on p-M-n junction (p-type Si, a thin metal and a n-type Si) where a Schottky contact barrier issue is of concern, the proposed WTe₂/HfS₂ heterojunction has the advantage of type III band alignment with sharp potential edges, a key to realize a cold source. The transport characteristics of 2D WTe₂/HfS₂ CSEFT are demonstrated. 2D WTe₂/HfS₂ heterostructure can be doped to adjust the band alignment and produces high on-state current. This study provides designing guidance to nanoelectronic device optimization of CSFET.