TFET accurate physically based models are highly required to analyze and predict the device characteristics for its future utilization in circuits. In order to precisely model TFETs, it is essential to understand the several aspects related to the physics-based modeling of these devices. Using 2D TCAD simulation, we showed that in order to appropriately model the electrostatic potential in InAs-based TFETs, the electron quasi-Fermi potential (eQFP) should be taken to depend on biasing conditions, both V DS and V GS , contrary to the case of Si-based TFETs in which the eQFP is considered independent of V GS which is widely encountered in the literature. The study is carried out for InAs double-gate homojunction tunnel FETs (DG-TFETs). In addition, we applied the main key factor of dependence of eQFP on a modified TFET model and it is revealed that the interpretation of eQFP correctly predicts the electrostatic potential and the drain-to-source band to band tunneling current.