Etching trenches to effectively create electron quantum wires for single-electron-transistor applications

Abstract

By self-consistently solving two-dimensional Schrödinger and Poisson equations, we have studied electron quantum wires formed by etching two shallow trenches in GaAs/InGaAs/AlGaAs and GaAs/AlGaAs heterostructures for single-electron-transistor applications. Two-dimensional electron gases (2DEGs) form in the InGaAs layer in GaAs/InGaAs/AlGaAs and at the GaAs/AlGaAs interface in GaAs/AlGaAs heterostructure, the two etched trenches deplete the carriers of the 2DEGs underneath and thus effectively define an electron quantum wire. It has been determined that two etched trenches with a depth of 50 nm and a spatial separation of 250 nm are optimal to create an electron quantum wire in a GaAs/InGaAs/AlGaAs heterostructure with a cross section of 80×10 nm2 and a peak electron concentration of 1.5×1018 cm−3 at 4.2 K.