Realization of BaZrS₃ chalcogenide perovskite thin films for optoelectronics

BaZrS₃, a prototypical chalcogenide perovskite, has not yet been deeply explored despite being first synthesized in the mid-1950s. In recent years, several publications on powder samples reveal that BaZrS₃ has a direct band gap of 1.7 to 1.8 eV, a high stability against moisture and pressure, and a very strong interaction with light. However, many of the fundamental properties still remain unknown due to the lack of film samples. Here we report the fabrication of BaZrS₃ thin films, by sulfurization of corresponding BaZrO₃ films deposited by pulsed laser deposition. Transport measurements indicate the films are n-type semiconductors with carrier densities in the range of 10¹⁹ to 10²⁰ cm^-3. The hall mobility ranges from 2.1 to 13.7 cm²/Vs depending on the sulfurization temperature. UV-Vis result shows an absorption coefficient of >10⁵ cm^-1 at a photon energy of >1.97eV and temperature dependent conductivity measurements reveal shallow donor level with an activation energy of several milli-electron volts. Our results assure that BaZrS₃ is a promising candidate material for optoelectronics.