Structural and Electronic Properties of the Graphene-Like Carbon Nitride Nanosheets

Using the Density Functional Theory (DFT) within the Local Density Approximation (LDA-PWC) and Generalized Gradient Approximation (GGA-PBE) we analyzed the structural and electronic properties for the two-dimensional carbon nitride compound, which was modeled by a finite C _n N _m H _k system. This cluster is amenable for the study of the effects of the geometry on the local electronic properties of the carbon nitride sheets. There were considered circular (armchair edge), triangular (zig–zag edge) and rectangular (zig–zag edge) cluster models. The obtainment of non-complex frequencies was used as criteria for structural stability of the optimized geometries. The circular sheet is the unique stable structure with non-planar optimized geometry. The results for the electronic structure show high polarity (4.15 D) for the carbon nitride sheet (neutrally charged), which is a different behavior as those observed for the carbon and boron nitride counterparts. The HOMO-LUMO energy gap, 1.16 eV, indicates a semiconductor behavior for the carbon nitride compounds. For the stable nanosheet an increase on the chemical reactivity in the case of cation charge (+ 1) is observed.