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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.

Advances in nanophotonics have shown the potential of colloidal metal nanoparticles with sharp tips, such as rods, to focalize plasmonic electromagnetic fields. We report on the synthesis of Au nanorods via a seed mediated approach and the influence of silver ions on the aspect ratio of the Au nanorods. The longitudinal surface plasmon resonance (LSPR) of the Au nanorods was successfully tuned with the concentration of silver ions. The surface enhanced Raman scattering (SERS) effect of 2-aminothiophenol (2-ATP) as a probe molecule on Au nanorods was systematically studied by varying the longitudinal surface plasmon resonance of the nanorods. The highest electromagnetic enhancement was observed when the longitudinal surface plasmon resonance of the Au nanorods overlapped with the laser excitation wavelength. The variation of the SERS enhancement factor with the longitudinal surface plasmon resonance and laser excitation lines is also discussed in detail.

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