Design and realization of Ohmic and Schottky interfaces for oxide electronics

TL;DR

This paper designs and experimentally validates oxide/oxide interfaces with Ohmic and Schottky characteristics, predicting band alignment and charge transfer in ABO3 perovskites, enabling tailored oxide electronics.

Contribution

It introduces a novel method for predicting band alignment and charge transfer in complex ABO3 perovskites, surpassing simple semiconductor rules.

Findings

High charge accumulation in SrTiO3 with Nb and Ta B-sites.

Formation of high mobility metallic interfaces for B=Nb and Ta.

No charge transfer for B=V, enabling conductive epitaxial gate metals.

Abstract

Understanding band alignment and charge transfer at complex oxide interfaces is critical to tailoring and utilizing their diverse functionality. Towards this goal, we design and experimentally validate both Ohmic- and Schottky-like charge transfers at oxide/oxide semiconductor/metal interfaces. We utilize a method for predicting band alignment and charge transfer in ABO3 perovskites, where previously established rules for simple semiconductors fail. The prototypical systems chosen are the rare class of oxide metals, SrBO3 with B=V-Ta, when interfaced with the multifaceted semiconducting oxide, SrTiO3. For B=Nb and Ta, we confirm that a large accumulation of charge occurs in SrTiO3 due to higher energy Nb and Ta d-states relative to Ti; this gives rise to a high mobility metallic interface, which is an ideal epitaxial oxide/oxide Ohmic contact. On the other hand, for B=V, there is no charge transfer into the SrTiO3 interface, which serves as a highly conductive epitaxial gate metal. Going beyond these specific cases, this work opens the door to integrating the vast phenomena of ABO3 perovskites into a wide range of practical devices.