Density Functional Theory studies of structural, electronic and optical properties of Fluorine Doped Magnesium Hydride

Abstract

In order to overcome the disadvantages of magnesium hydride (MgH2) towards its applications in solar cell science and technology, doping with non-metals such as Fluorine (F) doping is a promising approach to tune its large band gap. In order to expose the hidden potential in F doped MgH2, details analysis of electronic and optical absorptions is needed. Theoretical calculations of structural, electronic and optical properties of F doped MgH2 are studied using first-principles approach within density functional theory (DFT) framework. The calculated lattice constants with PBE-GGA are in better agreement with experimental result. The bandgap value of 3.34 eV for the undoped MgH2 is close to experimental value. When one atom of F is introduced into MgH2 at Mg site, the doping effects modified the band gap from 3.34 to 2.72 eV. Also, by introducing one atom of F to H site, the band gap value reduced to 1.59 eV. Our findings confirmed that non-metal doping narrow the energy band gap of semiconductor materials. The results of optical absorptions indicate that F doped MgH2 at H has strong absorption behavior in the visible light frequency, which depicts its suitability for solar cell applications.