Electronic properties of pristine and doped graphitic germanium carbide nanomeshes

Graphitic germanium carbide (g-GeC) is a novel material that has recently aroused much interest. Porous g-GeC can be fabricated by forming a lattice of pores in pristine g-GeC. In this work, we systematically investigate the influence of creating pores within pristine g-GeC. The pores are passivated with hydrogen, nitrogen, and oxygen, with four supercell sizes. The electronic properties are calculated using the density functional theory (DFT) formalism, which revealed that hydrogen-passivated systems have bandgaps ranging from 1.80 eV to 1.93 eV. The corresponding ranges for the nitrogen- and oxygen-passivated systems are 1.21 eV to 1.58 eV, and 1.18 eV to 1.45 eV, respectively. The bandgaps are always smaller than that of the pristine g-GeC system, and they approach the pristine value for larger supercell sizes. The studied systems have charge-trapping clusters of states located above/below the valence/conduction bands, partially localized at the pore-edge atoms. Additionally, we explore the chelation doping of the N-passivated GeC nanomesh using transition metal (Ni, Pd, Pt) three-atom clusters. Interestingly, the doped systems are dilute magnetic semiconductors. The studied systems exhibit electronic properties that may be useful for sensing and spintronics.