High room temperature mobility in Al₂O₃/SrTiO₃ heterostructures

¹ Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Department of Physics, Tianjin University - Tianjin 300354, China
² School of Material Science and Engineering, Hebei University of Technology - Tianjin 300130, China
³ School of Science, Tianjin University of Technology - Tianjin, 300384, China
⁴ State Key Laboratory of Infrared Physics, Chinese Academy of Sciences, Shanghai Institute of Technical Physics Shanghai 200083, China

^(a) khgao@tju.edu.cn (corresponding author)
^(b) sunny@mail.sitp.ac.cn

Received: 28 November 2021
Accepted: 31 May 2022

Abstract

Al₂O₃/SrTiO₃ heterostructures have attracted wide attention because of high electron mobility at cryogenic temperatures. But very low room temperature mobility (typically less than 12 cm²V⁻¹s⁻¹) limits its potential application. Here, the Al₂O₃/SrTiO₃ heterostructures are successfully prepared by the low-cost magnetron sputtering. We observed that room temperature mobility is gradually enhanced on increasing electron concentration, and a maximum of 41.1 cm²V⁻¹s⁻¹ is obtained. This can be attributed to the high electron concentration due to the longitudinal optical phonon scattering. Our findings not only offer a route to improve room temperature mobility of the SrTiO₃-based heterostructures but also provide a new experimental method for fabricating Al₂O₃/SrTiO₃ heterostructures.