Thermal stability and optical properties of Sc-doped copper nitride films

Sc-doped copper nitride (Cu3N) films were prepared by reactive magnetron sputtering equipment at room temperature with a preferred orientation of (111). XRD and XPS figures indicate that Sc atoms substitute for the Cu in the lattice. The much smaller grain size and the more compact surface can be discovered from the result of SEM after Sc doping. Sc-doped Cu3N films are more thermally stable than the pure Cu3N films when the Sc doping concentration is 1.3 at.% with the sputtering power of 80 W. The band gap of slight Sc doping sample (0.45 at.%) is increased from 1.24 to 1.45 eV. However, it drops gradually (from 1.45 to 1.16 eV) with the increasing of Sc content.