Supertetrahedraphene: A novel quasi 2D carbon allotrope with controllable thickness and electronic properties

A novel all-carbon material with quasi 2D character, supertetrahedraphene, was proposed using carbon tetrahedron as the starting material. The geometry and electronic properties were investigated via density functional theory (DFT) calculations. Supertetrahedraphene was confirmed to be an energetically meta-stable and dynamically stable semiconductor with an indirect band gap of 2.80 eV. An acetylenic linkage ([sbnd]C[tbnd]C[sbnd]) was inserted to change the height of supertetrahedraphene, resulting in a new sp + sp³ hybrid system. Insertion of [sbnd]C[tbnd]C[sbnd] can further stabilize supertetrahedraphene and transform it to a semiconductor with direct band gaps. These band gaps steadily decrease as the number of [sbnd]C[tbnd]C[sbnd] increases, and the supertetrahedraphene is predicted to be metallic if the [sbnd]C[tbnd]C[sbnd] is of sufficient length. Our results suggest a strategy to design novel carbon materials with desired properties.