Nanocrystalline NiO structure: preferred oriented growth

Abstract

Nickel oxide (NiO) nanostructures were deposited on Si (100), potassium bromide (KBr), and glass slidesubstrates at room temperature by the evaporation technique. The prepared samples were annealed at temperatures of400◦C and 600◦C in air atmosphere. The structure, morphology, crystalline phase, optical properties, and chemicalbonding of nanocrystalline nickel oxide were investigated by scanning electron microscopy (SEM), X-ray diffraction(XRD), UV-visible absorption spectrum, and FT-IR spectroscopy.XRD results and SEM images showed that nickel oxide nanoparticles have preferred orientation with uniformsize distribution. The as-deposited lms showed preferred orientation (texture) growth. As the lms were annealed, thecrystallites were agglomerated to form bigger particles. Optical properties were identi ed by measuring transmittanceusing a UV-Vis spectrophotometer. Optical constants such as the refractive index n, the extinction coefficient k, andthe lms' thickness and roughness were calculated from transmittance data using a reverse engineering method. As thesample annealed, the ad-atom surface mobility increased, and smaller crystallites agglomerated to form bigger ones.