Defective behavior, electronic and optical properties of Sc and Y doped Pnma MgGeN2

Abstract

In this work the defective behavior and the electronic & optical properties were investigated for Scandium (Sc) and Yttrium (Y) doped Pnma phase of MgGeN${}_2$ using density function theory (DFT) calculations. First, the occupation of dopants was studied with the formation energy of single defect and binding energy between defects, where single Sc or Y dopant would like to occupy the Mg site, while the second Sc dopant will occupy the interlayer Ge site and the second Y dopant prefers occupy the intralayer Ge site. When Sc and Y are simultaneously doped and close enough, the Sc will occupy the Mg site and Y will occupy the interlayer Ge site. Moreover, the light absorption has been enhanced by doping in visible and near ultraviolet range as well as the high energy region above 20 eV, and decreased between 10 eV and 20 eV. Therefore, the doping with Sc/Y can be used to modulate the properties of Pnma phase MgGeN${}_2$ and hence widen its applications.