Optical and Electronic Structural Properties of Cu(3)N Thin Films: A First-Principles Study (LDA + U)

[Image: see text] A comprehensive study on the electronic structure and optical properties of a Cu(3)N film is performed by the first-principles study using density functional theory. The Hubbard (U) term is added in the local density approximation approach for improvement of the theoretical band gap energy. The band structure of the Cu(3)N unit cell shows a strong hybridization of Cu 3d and N 2p orbitals in the near-valence band region (M) because of their antibonding states which are also observed by molecular orbitals (HOMO–LUMO). The conduction band is dominated by a very small amount of Cu 3p and N 2p orbitals. The density of states exhibits a negligible deformation in Cu–N bonding. The Cu(3)N thin film deposited by the DC magnetron-sputtering technique shows a polycrystalline structure with a nonstoichiometric Cu(3)N phase. The experimentally obtained optical band gap and refractive index of the Cu(3)N film are 1.44 eV and 2.14, respectively, which are comparable with those from the theoretical approximation.