Investigating the Impact of Ge-Quantum Well Width in Si/SiO2/Ge/SiO2/Pt Resonant Tunneling Device with NEGF Formalism

Abstract

In this work, a Si/SiO2/Ge/SiO2/Pt resonant tunneling device (RTD) with an asymmetric double barrier has been modeled by adopting NEGF formalism. The impact of Ge-quantum well widths below, equal, and above its excitonic Bohr radius (EBR ~ 25 nm) on resonant tunneling current is investigated at room temperature. The tunneling current peaks are observed to appear for decreasing the well width to equal or less than the EBR of Ge. Such peak values increase with downscaling of the well width up to a certain value and then it decreases with further miniaturization. The maximum peak current is obtained to be ~ 13 mA/cm2 for Ge-well width of 17 nm. The corresponding maximum peak-to-valley current ratio (PVCR) is estimated to be ~ 18 at room temperature, which is larger in order than the conventional RTDs. Therefore, the current work may provide the route for fabrication of Si/Ge-based high performance resonant tunneling devices operational at room temperature.