Effect of doping and defects on the optoelectronic properties of ZrSe₂ based on the first principle

Based on the first principles under the framework of density functional theory, it calculates the effect of vacancy defects in single Zr and single Se atoms and the replacement of Se atoms in ZrSe₂ with O, Se, and Te atoms on the optoelectronic properties of monolayer ZrSe₂, including geometry, energy band structure, electronic density of states, and optical properties. The doping of the three non-metallic atoms was n-type doping for the O and S atoms and p-type doping for the Te atom. Defects in the Zr atoms and O-atom doping significantly affect the peak reflectance and absorption coefficient of the ZrSe₂ system.

All Density Functional Theory calculations were carried out using the CASTEP module in the Materials-Studio (MS) software. The generalized gradient approximation plane-wave pseudopotential method and the Perdew-Burke-Ernzerfhof (PBE) generalized function were used for structural optimization and total energy calculation of the defect and doping systems. After convergence tests, the plane wave truncation energy was set to 500 eV, and the Brillouin zone K-point grid was set to 4 × 4 × 1. The atomic energy convergence criterion is 1.0 × 10^-6 eV/atom, the interatomic interaction force convergence criterion is 0.02 eV/Å, the maximum atomic displacement convergence criterion is 0.001 Å, and the internal crystal stress convergence criterion is 0.05 GPa. In order to avoid the influence of the interaction forces between the layers, a vacuum layer of 15 Å is placed in the Z-axis direction.