Effective mass and optical properties of orthorhombic Al<inf>1−x</inf>In<inf>x</inf>FeO<inf>3</inf> perovskite: An ab-initio study

Electronic and optical properties of AlFeO3 and Al1−xInxFeO3 (x = 0.25, 0.5, 0.75) are studied using ab-initio calculations. Electronic structure in the vicinity of the conduction band minimum (CBM) and valence band maximum (VBM), the effective masses of holes and electrons at the gamma point are calculated. The calculated effective masses of electrons is smaller than that of holes (mc1⊥, mc1‖ (me*) < mv1⊥, mv1‖, mv2⊥, mv2‖ (mh*)), for all values of x; this is expected to contribute to the desirable photocatalytic performance. Effective mass tensor for electrons is found to be isotropic (unlike holes). The optical constants such as static dielectric constant, refractive index, extinction coefficient and absorption coefficient are comparable with that Si. The maximum absorption exists in the visible light region for all the phases studied; making In-doped AlFeO3 suitable for energy harvesting applications. We noted from our previous work (Sudha Priyanga and Thomas, 2018) that the computed band gap values could be underestimated by as large as ∼0.5 eV. Even so, the reported phases would be relevant for light harvesting.