Structural and electronic properties of C3N4−nPn (n=0,1,2,3,4)

First principles electronic structure method based on the density functional theory and the local density approximation is used to investigate the structural and electronic properties of C3N4−nPn (n=0,1,2,3,4). It is found that the N-rich compounds energetically favor structures with sp2 bonding, while the pseudocubic structure which is characterized by sp3 bonding is preferred by the P-rich compounds. Even though C3N4 is a wide-gap semiconductor, the band gap of C3N4−nPn decreases rapidly when N is gradually substituted with P, and the P-rich compounds are predicted to be metallic or narrow-gap semiconductors.