Two-dimensional electron gas in piezotronic devices

Abstract

Recent developments of piezotronic devices start to focus on the quantum behaviors of the nanostructured system going beyond the conventional device applications. Piezotronic devices utilize piezoelectric field to control the charge carrier behaviors at the junction, contact or interface of piezoelectric semiconductor, such as ZnO, GaN, and two-dimensional materials. In this study, we theoretically investigate the piezoelectric field effect on two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructure by employing an approximate triangular potential model. Basic electronic properties such as wave function, electronic energy, electronic density distribution and the width of potential well are explored under the influence of the externally applied strain. From the electronic density, bound state can be eliminated or created by properly changing the external strain, meaning the effective modulation of piezotronic effect on quantum states. The piezoelectric field in 2DEG system is perpendicular to the electronic transport, which has remarkable advantage over the parallel case in switching devices. Furthermore, piezoelectric modulation of intrasubband transition enriches the fundamental theory of piezo-photonics and provides guidance for designing strain-gated infrared devices.