First principles study on structural, electronic and optical properties of 3d transition metals-substituted CuGaSe2

Intermediate band solar cells (IBSCs) use materials characterized by an electronic band between the valence and conduction bands of the conventional semiconductor. Consequently, an increase in light absorption below the host gap due to this added intermediate band. Transition-metal doped chalcopyrite can be potential candidates for this aim. In this work, a Ga atom of the CuGaSe2 chalcopyrite is substituted by 3d transition metal M (M = Sc, V, Ti, Cr or Zn) atoms. To understand this substitution effect, we investigated formation energies, electronic structures, and optical properties of CuGaSe2 and CuGa0.75M0.25Se2 using the density functional theory (DFT). We used generalized gradient approximation (PBEsol), reliable for new systems, within projector-augmented wave (PAW) method to examine structural, electronic and optical properties of CuGa0.75M0.25Se2. Electronic and optical properties of CuGaSe2 were calculated using hybrid functional (HSE06) closer to experiment. We reported here the structural parameters, electronic densities of states and the absorption coefficients for CuGaSe2 and CuGa0.75M0.25Se2 systems.