Oxide heterostructures for high density 2D electron gases on GaAs

Abstract

2D electron gases (2DEGs) that form at oxide interfaces provide a rich testbed of phenomena for condensed matter research, with emerging implementations in devices. Integrating such oxide systems with semiconductors advances these interesting phenomena toward technological applications. This approach further opens prospects of new functionalities arising from the potential to couple the 2DEG carriers with the semiconductor. In this work, we demonstrate the first integration of oxide 2DEGs with a direct bandgap III-V semiconductor. The growth and structural characteristics of (001) GdTiO3-SrTiO3 (GTO–STO) heterostructures on (001) GaAs are described. Analysis of the magnetotransport data yields a high electron density of ∼2 × 1014 cm−2 per GTO–STO interface, and points to the oxide interface as the source of the carriers. The effect of structure and defects on the transport properties is discussed within the context of the growth conditions and their limitations. These results provide a route for integrating oxide 2DEGs and other functional oxides with GaAs toward future device prospects and integration schemes.