In this paper the analytical models of quantum mechanical tunneling concepts are discussed. Double gate (DG) tunnel field effect transistors (TFETs) with gate-drain overlap have been proposed from the perspective of improving the device performance in terms of the drive current (ION). In the gate-drain overlap region, an asymmetric gate oxide is introduced and compared to that of DG TFET without overlap. The physics and performance of the devices are analyzed using different materials such as Si, SiGe, InAs and GaSb. Higher tunneling probability is observed for DG TFETs with gate-drain overlap compared to that of DG TFETs without overlap. Furthermore, GaSb based DG TFETs have shown an excellent improvement in the device performance by offering high ION of 1.15 mA/μm. © 2019 IEEE.