Nanocrystalline ZnO films prepared by pyrolysis of Zn-arachidate LB multilayers

Nanocrystalline, zinc oxide films have been formed by the pyrolysis of zinc arachidate LB multilayers in oxygen ambient. FT-IR and UV-vis spectroscopy showed that on heat treatment, the pyrolysis began at ∼200 °C and was complete at ∼350 °C. TEM studies showed that the heat treatment results in the formation of a continuous and uniform ZnO film consisting of nanocrystallites of size 5 ± 2 nm. Electron diffraction studies show that the film consists of an unusual phase reported as “leafy and thin platy crystal”, obtained under high-pressure conditions. The band gap of the film, estimated from a plot of α versus hν was found to be ∼3.3 eV. It is interesting to note that the presence of the unusual phase and nanocrystalline nature do not have a significant effect on the optical gap of the ZnO film.