Sol-gel formation of ordered nanostructured doped ZnO films

A novel sol-gel route to c-axis oriented undoped and Co, Fe and Mn doped ZnO films is reported. Sols were prepared from a hydrated zinc acetate precursor and dimethylformamide (DMF) solvent. Films were spin-coated on to hydrophilic sapphire substrates then dried, annealed and post-annealed, producing almost purely uniaxial ZnO nanocrystallites and a high degree of long-range structural order. Specific orientation of hexagonal crystallites is demonstrated both perpendicular and parallel to the substrate surface. Cobalt doping resulted in the formation of disconnected oriented ZnO nanocrystals. Vanadium doped films formed the spinel oxide ZnAl₂O₄. Structural, optical and morphological characterisation demonstrated the high quality of the films and shows the suitability of the method for cost-effective fabrication studies in areas of oxide research that traditionally employ epitaxial growth techniques.