Effect of nitrogen pressure on structure and optical band gap of copper nitride thin films
氮分压对氮化铜薄膜结构及光学带隙的影响

Copper nitride(Cu_3N)thin films were deposited on glass substrates by reactive radio frequency magnetron sputtering under different radio frequency power(P)and nitrogen partial pressure r(r=N_2/N_2 Ar]).The thickness,crystalline structure and surface morphology of films were characterized by profilometer,X-ray diffraction(XRD)and atomic force microscopy(AFM),respectively.The optical transmission spectrum was obtained by an ultraviolet-visible(UV-VIS)spectrophotometer and the optical band gap(E_g)was calculated.The results suggest that the films' deposition rate increases with P and r.The surface of the films reveals a compact structure,and the grain size of Cu_3N is about 30nm.Meanwhile,with increasing r,the grain size and optical band gap of Cu_3N increase,of which E_g ranges from 1.47 to 1.82eV,and the films' growth prefers the(111)direction at low r and the(100)direction at high r.