High Mobility 2DEG in modulation-doped \b{eta}-(AlxGa1-x)2O3/Ga2O3 heterostructures

TL;DR

This paper reports the first observation of high-mobility 2DEG in modulation-doped ta-(AlxGa1-x)2O3/Ga2O3 heterostructures, demonstrating potential for advanced electronic and quantum devices using this wide bandgap material system.

Contribution

It introduces a novel high-mobility 2DEG in ta-(AlxGa1-x)2O3/Ga2O3 heterostructures via modulation doping, with experimental evidence including Shubnikov-de Haas oscillations.

Findings

First observation of Shubnikov-de Haas oscillations in this heterostructure

Peak low-temperature mobility of 2790 cm/Vs

High-quality heterojunction confirmed by temperature-dependent carrier density

Abstract

Beta-phase Ga2O3 has emerged as a promising candidate for a wide range of device applications, including power electronic devices, radio-frequency devices and solar-blind photodetectors. The wide bandgap energy and the predicted high breakdown field, together with the availability of low-cost native substrates, make \b{eta}-Ga2O3 a promising material compared to other conventional wide bandgap materials, such as GaN and SiC. Alloying of Al with \b{eta}-Ga2O3 could enable even larger band gap materials, and provide more flexibility for electronic and optoelectronic device design. In this work, we demonstrate a high mobility two-dimensional electron gas (2DEG) formed at the \b{eta}-(AlxGa1-x)2O3/Ga2O3 interface through modulation doping. Shubnikov-de Haas oscillation was observed for the first time in the modulation-doped \b{eta}-(AlxGa1-x)2O3/Ga2O3 structure, indicating a high-quality channel formed at the heterojunction interface. The formation of the 2DEG channel was further confirmed by a weak temperature-dependence of the carrier density, and the peak low temperature mobility was found to be 2790 cm2/Vs, which is significantly higher than can be achieved in bulk-doped \b{eta}-Ga2O3. The demonstrated modulation-doped \b{eta}-(AlxGa1-x)2O3/Ga2O3 structure lays the foundation for future exploration of quantum physical phenomena as well as new semiconductor device technologies based on the \b{eta}-Ga2O3 material system.