Nanostructured mesoporous nickel oxide thin films

Nanostructured nickel oxide thin films were prepared by the pulsed laser ablation technique. The effects of annealing on the structural, morphological, electrical and optical properties are discussed. Phase imaging was used to examine the surface contaminants, adhesion and hardness and height imaging to evaluate the height profile of the films. Morphological investigations using atomic force microscopy and scanning electron microscopy indicate a strong influence of the annealing process on the surface roughness and particle size. A self-assembly of nanocrystals agglomerating together to form an island-like structure is observed in films annealed at 773 K. X-ray diffraction and x-ray photoelectron spectroscopy investigations indicate the presence of Ni2O3 in the as-deposited films. A transformation to cubic NiO with growth along ( 111) and ( 200) planes with increase of annealing temperature is also observed.