Recently L-shaped tunneling field-effect-transistor (LTFET) has been introduced to overcome the thermal subthreshold limit of conventional metal-oxide-semiconductor field-effect-transistors (MOSFET). In this work, shortcoming of LTFET was investigated. It was found that corner effect present in LTFET effectively degrades its subthreshold slope. To get rid of corner effect a new type of device with dual material gates is presented. The new device termed as DG-LTFET gets rid of the corner effect and results in a significantly improved subthreshold slope of less than 10 mV/dec, and an improved ON/OFF current ratio over LTFET. In this work DG-LTFET was evaluated for different device parameters, and bench-marked against LTFET. This work presents an optimum configuration of DG-LTFET in terms of device dimensions and doping levels, to get the best subthreshold, ON current and ambipolar performance from the DG-LTFET.