IMPACT OF DEFECT ON ELECTRONIC AND OPTICAL PROPERTIES OF SEMICONDUCTING TROILITE IRON SULFIDE (FeS) Ari Sulistyowati, Fahdzi Muttaqien
a) Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology
arisulistyowati97[at]gmail.com
b) Majoring in Computational Science, Bandung Institute of Technology
Abstract
Iron Sulfide (FeS) has attracted significant attention due to its unique properties, which include both semiconductor and metallic characteristics. However, FeS does not naturally maintain the same ratio between iron and sulfur atoms (1:1), resulting in the creation of point defects known as FeS troilite and FeS pyrite, where deviations occur in the iron or sulfur atoms. The distinctive qualities of FeS have attracted the interest of researchers on a global scale. In this study, a combination of density functional theory (DFT) and van der Waals functional was used to investigate how defects impact the electronic and optical properties of FeS troilite structures. Our findings illustrate that introducing a single defect in the iron atoms, which comprise 2.08% of the structure, triggers a significant shift in the energy gap, reducing it from 0.78 eV (pristine structure) to 0 eV. This important change indicates a fundamental change from semiconductor to metal. In addition, computational analysis shows that defects also contribute to the narrowing of the band gap in iron-deficient FeS troilite. These insights enhance our understanding of the interplay between defects and properties in FeS, paving the way for customized applications in various technological domains.
Keywords: Iron Sulfide, troilite FeS, point defects, density functional theory, electronic properties, optical properties, ban gap
