Ionically conducting oxide composite thin films and heterostructures

Ionic conductivity in oxide composite thin films has recently drawn growing attention due to the unique interfacial phenomena and huge application potential. In this review article the author presents the recent progress in three materials classes including (1) the single-layer heteroepitaxial structures, (2) multilayer structures, and (3) vertically aligned heteroepitaxial structures. This review aims to give an overview of this field and offer guidelines to understand the interfacial phenomena. Two promising research directions in this field are proposed at the end, including understanding the interfacial phenomena in heterostructures, and exploring new methods which can separate thin films from their substrates. This review was submitted as part of the 2017 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged