Electric field tunable bandgap and anisotropic high carrier mobility in SiAs2/GeAs2 lateral heterostructure

Abstract

The structural and electronic properties of SiAs2/GeAs2 in-plane lateral heterostructure (LHS) with and without an external electric field (Eext) perpendicular to the LHS plane were investigated by first-principles calculations. Our data show that the LHS with a zigzag interface is dynamically stable, which possesses a type-I band alignment with an indirect bandgap of 1.86 eV and highly anisotropic carrier mobility. When the Eext is applied, the LHS band gap decreases owing to the giant Stark effect, and the indirect-to-direct band transition occurs between −0.1 V/Å and −0.2 V/Å. Notably, the Eext can also tune the anisotropy and magnitude of the hole-dominated carrier mobility in the SiAs2/GeAs2 LHS due to the field-induced charge redistribution. Indeed, the hole mobility along the x-direction can be enhanced up to 160%, from 498 cm2V-1s−1 at 0 V/Å to 817 cm2V-1s−1 at 0.4 V/Å, while the anisotropic factor for the hole varies nonlinearly from 7.8 at 0 V/Å to 4.9 at 0.4 V/Å. The SiAs2/GeAs2 LHS with electric field tunable bandgap and anisotropic high carrier mobility may hold promise for applications of IV-V LHSs in anisotropic electronic materials and devices.