Electronic structure and optical properties of iron based chalcogenide FeX₂ (X = S, Se, Te) for photovoltaic applications: a first principle study

Abstract

In present work, the electronic structure and optical properties of the FeX₂ (X = S, Se, Te) compounds have been evaluated by the density functional theory based on the scalar-relativistic full potential linear augmented plane wave method via Wien2K. From the total energy calculations, it has been found that all the compounds have direct band nature, which determined by iron 3d states at valance band edge and anion p dominated at conduction band at Γ-point and the fundamental band gap between the valence band and conduction band are estimated 1.40, 1.02 and 0.88 eV respectively with scissor correction for FeS₂, FeSe₂ and FeTe₂ which are close to the experimental values. The optical properties such as dielectric tensor components and the absorption coefficient of these materials are determined in order to investigate their usefulness in photovoltaic applications.