2024/05/27 by Garima Aggarwal, Aggarwal, Garima, Adeem Saeed Mirza +15 · 1 citation
Engineering · Materials Science · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Perovskite Materials and Applications #Solid-state spectroscopy and crystallography #Thermal Expansion and Ionic Conductivity
paper · pdf · doi:10.48550/arxiv.2405.17327
openalex publication_date 2024/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Exploring the conduction mechanism in the chalcogenide perovskite BaZrS3 is of significant interest due to its potential suitability as a top absorber layer in silicon-based tandem solar cells and other optoelectronic applications. Theoretical and experimental studies anticipate native ambipolar doping in BaZrS3, although experimental validation remains limited. This study reveals a transition from highly insulating behavior to n-type conductivity in BaZrS3 through annealing in an S-poor environment. BaZrS3 thin films are synthesized via a two step process: co-sputtering of Ba-Zr followed by sulfurization at 600 ∘C, and subsequent annealing in high vacuum. UV-Vis measurement reveal a red-shift in the absorption edge concurrent with sample color darkening after annealing. The increase in defect density with vacuum annealing, coupled with low activation energy and n-type character of defects, strongly suggests that sulfur vacancies (VS) are responsible, in agreement with theoretical predictions. The shift of the Fermi level towards conduction band minimum, quantified by Hard X-ray Photoelectron Spectroscopy (Ga Kα, 9.25 keV), further corroborates the induced n-type of conductivity in annealed samples. Our findings indicate that vacuum annealing induces VS defects that dominate the charge transport, thereby making BaZrS3 an n-type semiconductor under S-poor conditions. This study offers crucial insights into understanding the defect properties of BaZrS3, facilitating further improvements for its use in solar cell applications.