Spectroscopic ellipsometry study of thin NiO films grown on Si (100) by atomic layer deposition

Thin NiO films are grown at $300°C$ on Si (100) using atomic layer deposition. The dependence of annealing temperature on the optical properties of NiO films has been investigated using spectroscopic ellipsometry in the spectral region of $1.24–5.05eV$⁠. It is found that the refractive index and thickness of NiO films are affected by high temperature annealing. The optical band gap of the as-deposited thin NiO film is determined to be $3.8eV$⁠, which is almost independent of the annealing temperature. The indirect band gap of NiO film shifts toward lower photon energy with an increase in annealing temperature.