Conducting LaAlO3/SrTiO3 heterointerfaces on atomically flat substrates prepared by deionized-water

TL;DR

This study demonstrates that water-leaching can produce atomically flat SrTiO3 substrates suitable for high-quality LaAlO3/SrTiO3 heterostructures, offering a safer alternative to traditional etching methods.

Contribution

The paper introduces a water-leaching method for preparing atomically flat SrTiO3 substrates, enabling high-quality heterostructure growth comparable to conventional methods.

Findings

Water-leaching produces atomically flat SrTiO3 substrates.

LAO/STO heterostructures on water-leached substrates show high structural and transport quality.

Water-leaching is a safer alternative for substrate preparation.

Abstract

We have investigated how the recently-developed water-leaching method for atomically-flat SrTiO3 (STO) substrates affects the transport properties of LaAlO3 (LAO) and STO heterointerfaces. Using pulsed laser deposition at identical growth conditions, we have synthesized epitaxial LAO thin-films on two different STO substrates, which are prepared by water-leaching and buffered hydrofluoric acid (BHF) etching methods. The structural, transport, and optical properties of LAO/STO heterostructures grown on water-leached substrates show the same high-quality as the samples grown on BHF-etched substrates. These results indicate that the water-leaching method can be used to grow complex oxide heterostructures with atomically well-defined heterointerfaces without safety concerns.