First principles study of structural, optoelectronic and thermoelectric properties of Cu₂CdSnX₄ (X = S, Se, Te) chalcogenides

In this work, structural, electronic, optical and thermoelectric properties of Cu₂CdSnX₄ (X = S, Se, Te) have been studied through the full potential linearized augmented plane wave method. Calculated ground state lattice parameters are in good agreement with the experimental results. Lattice constant and bulk moduli vary inversely by replacing the anion X from S to Te in Cu₂CdSnX₄. The WC-GGA shows that the materials are metallic in nature. The EV-GGA predicts better band gaps compared to WC-GGA. The calculated bandgap values are 1.8, 1.06 and 0.8042 for Cu₂CdSnX₄, Cu₂CdSnX₄, Cu₂CdSnX₄ respectively. Cd-d, Sn-s and X-p states contribute significantly in the density of states of the compounds. Absorption peaks and optical conductivity is high in the visible and ultraviolet energy regions. All the semiconductors have figure of merit above 0.70. The optical and thermoelectric properties clearly show that Cu₂CdSnX₄ are potential candidates in the fields of solar cell and thermoelectric technology.