First-principles study of structural, electronic and optoelectronic properties of Ag-doped Cu₂O alloys: TB-mBJ insights

The structural, electronic and optical properties of Cu2(1-x)Ag2xO alloys (x = 0, 0.25, 0.50, 0.75 and 1) have been investigated under the framework of the density functional theory (DFT), where the exchange and correlation potential is defined by the generalized gradient approximation of TB-mBJ (TB-mBJ-GGA). The equilibrium lattice constant (a(0)), bulk modulus (B-0) and its first-pressure derivative (B') are determined for each Cu2(1-x)Ag2xO alloys (x = 0, 0.25, 0.50, 0.75 and 1). Based on the equilibrium lattice parameters, the electronic structure of Ag-doped Cu2O alloys is investigated in order to identify the electronic behavior of each compound; this leads to the fact that all Cu2O, Cu1.50Ag0.50O, CuAgO, Cu0.50Ag1.50O and Ag2O compounds are semiconductors. Furthermore, the optical properties of these compounds are calculated such as the complex dielectric constant, the complex refractive index, the absorption coefficient and the optical reflectivity.