  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.
