Efficient energy gap tuning for T-carbon via single atomic doping

Abstract

T-carbon (TC), a new carbon allotrope recently proposed and fabricated wide band gap semiconductor, is constructed by substituting each carbon atom in diamond by a carbon tetrahedron. Although the porous and light-weighted characters provide various potential application possibilities, such as energy storage, photonic/electronic devices or catalysis, the wide band gap hindered its practicability. By examining various possible doping/substituting schemes to tune the electronic band gap of TC, we found that only group IVA single atom substitution of a carbon tetrahedron is stable. Other doping schemes, such as p/n-type doping or p-n type codoping, either collapse during structural relaxation or has large imaginary phonon modes. The band gaps can be effectively tuned in the range 1.62–3.63 eV with group IVA substitution. In particular, the Pb doped TC strongly absorbs in the visible range, combined with the localized conduction band minimum in the vicinity of the dopant, implies its potential applicability as a good photocatalyst.