Epitaxial Thin Films of a Chalcogenide Perovskite

TL;DR

This paper demonstrates the successful growth and characterization of epitaxial BaZrS3 thin films, revealing their structural, optical, and electronic properties, and enabling future device applications of chalcogenide perovskites.

Contribution

It reports the first epitaxial growth of BaZrS3 thin films using pulsed laser deposition and characterizes their structural and optoelectronic properties.

Findings

Films are strongly textured and epitaxial at the interface.

Films exhibit strong light absorption and photoluminescence.

Photodetectors made from these films show high ON/OFF ratios.

Abstract

Chalcogenide perovskites have emerged as a new class of electronic materials, but fundamental properties and applications of chalcogenide perovskites remain limited by the lack of high quality epitaxial thin films. We report epitaxial thin film growth of BaZrS3, a prototypical chalcogenide, by pulsed laser deposition. X-ray diffraction studies show that the films are strongly textured out of plane and have a clear in-plane epitaxial relationship with the substrate. Electron microscopy studies confirm the presence of epitaxy for the first few layers of the film at the interface, even though away from the interface the films are polycrystalline with a large number of extended defects suggesting the potential for further improvement in growth. X-Ray reflectivity and atomic force microscopy show smooth film surfaces and interfaces between the substrate and the film. The films show strong light absorption near the band edge and photoluminescence in the visible region. The photodetector devices show fast and efficient photo response with the highest ON/OFF ratio reported for BaZrS3 films thus far. Our study opens up opportunities to realize epitaxial thin films, heterostructures, and superlattices of chalcogenide perovskites to probe fundamental physical phenomena and the resultant electronic and photonic device technologies.