Pressure and Temperature Dependent Raman Spectroscopy of Chalcogenide Perovskites

Inorganic semiconductors known as chalcogenide perovskites including BaZrS$_{3}$ and its alloys, show potential for application in photovoltaics. The phonon frequencies of BaZrS$_{3}$ have been investigated using Raman spectroscopy as a function of temperature from 14 K to 295 K at 1 atm, as well as a function of pressure up to 8.9 GPa at 295 K and up to 6.8 GPa at 120 K. In the range measured, pressure shifts of Raman peaks show no mode softening, indicating a robust and stable material in the Pnma space group. Due to this stability, BaZrS$_{3}$ serves as an excellent prototype for alloys occupying the same phase but having different unit cell volume. This volume change provides a method for band-gap tuning with the goal of more efficient energy harvesting. Results of these studies will be discussed.