Solution Monolayer Epitaxy for Tunable Atomically Sharp Oxide Interfaces

TL;DR

This paper introduces a rapid, cost-effective wet chemical method for creating atomically sharp oxide interfaces with high precision, enabling advanced nanodevice fabrication and p-type interface control.

Contribution

A novel self-limiting wet chemical process for epitaxial oxide layer deposition achieving atomically sharp interfaces with half-unit cell resolution.

Findings

Successful fabrication of SrTiO3/BaO/LaAlO3 heterostructures.

Transport properties show mixed electron-hole contributions.

Hole mobility surpasses electron mobility in the interfaces.

Abstract

Epitaxial growth of atomically-sharp interfaces serves as one of the main building blocks of nanofabrication. Such interfaces are crucial for the operation of various devices including transistors, photo-voltaic cells, and memory components. In order to avoid charge traps that may hamper the operation of such devices, it is critical for the layers to be atomically-sharp. Fabrication of atomically sharp interfaces normally requires ultra-high vacuum techniques and high substrate temperatures. We present here a new self-limiting wet chemical process for deposition of epitaxial layers from alkoxide precursors. This method is fast, cheap, and yields perfect interfaces as we validate by various analysis techniques. It allows the design of heterostructures with half-unit cell resolution. We demonstrate our method by designing hole-type oxide interfaces SrTiO3/BaO/LaAlO3. We show that transport through this interface exhibits properties of mixed electron-hole contributions with hole mobility exceeding that of electrons. Our method and results are an important step forward towards a controllable design of a p-type oxide interface.