First-principles based ballistic transport simulation of monolayer and few-layer InSe FETs

Ballistic performance of monolayer and few-layer indium selenide (InSe) based field effect transistors (FETs) is evaluated based on first principles calculation using density functional theory (DFT) and top-of-the-barrier transport model. Quantum confinement in atomically layered InSe is taken into account by self-consistently solving the Poisson and Schrodinger equations based on effective mass approximation. DFT calculations suggest that the electronic band structure of layered InSe strongly depend on the layer number, where the bandgap energy as well as electron effective mass gradually increases with layer number decreasing. Ballistic transport property as a function of layer number in InSe FET is calculated based on the thickness-dependent effective mass, and analyzed by the inversion density, injection velocity and quantum capacitance separately. Simulation results reveal that the InSe FETs with reduced layer number provide better electronic performance, showing great potential for future high-performance complementary metal-oxide-semiconductor application. (C) 2019 The Japan Society of Applied Physics