Optical properties of amorphous and polycrystalline Sb_2Se_3 thin films prepared by thermal evaporation

摘要

Sb_2Se_3 is a very promising photovoltaic material because of its attractive material, optical and electrical properties. Very recently, we reported a superstrate CdS/Sb_2Se_3 solar cell with 5.6% certified efficiency. In this letter, we focused on the optical properties of amorphous and polycrystalline Sb_2Se_3 thin films prepared by thermal evaporation. Using temperature dependent transmission spectrum and temperature dependent photoluminescence, the indirect optical transition nature and bandgap values as functions of temperature were acquired. Using ellipsometry measurements and Swanepoel's envelope method, the refractive indices as well as the dielectric constant in a wide wavelength range of 193-2615 nm were obtained. These works would lay the foundation for the further development of Sb_2Se_3 thin film solar cells.