Electronic properties of hydrogen/fluorine adsorbed two-dimensional C568: A first-principles study

Adjusting the electronic band structure of two-dimensional (2D) carbon-568 (C₅₆₈) allotrope from indirect to direct can greatly expand its applications in photoelectric and optoelectronic fields. The electronic properties of C₅₆₈ and the effects of surface functionalization are investigated by the first-principles density-functional theory calculations. The surface functionalization including hydrogenation/fluorination shows that the band gap of C₅₆₈ can be tuned from indirect to direct under different H/F adsorption coverage. Meanwhile, the band gap of C₅₆₈ is widened and the work function is enlarged gradually with the increasing coverage of H/F. The mechanism for such variation of electronic properties in C₅₆₈ is analyzed by a detailed exploration of the electron charge density and wavefunction in this work.