Initial stages of the cubic-InN growth with the technique of the pre-deposition of indium

The initial stages of the cubic indium nitride film growth at 350 C were studied using low-pressure metal-organic chemical vapor deposition. The technique of the pre-deposition of indium was applied, that is, a layer of indium was first deposited on sapphire surface before the growth of InN. X-ray diffraction and X-ray photoelectron spectroscopy show that the pre-deposition of indium is able to promote the growth of InN films, and meanwhile, suppress the indium aggregation in the as-grown films. Atomic force microscopy images of InN films indicate that the predeposition of indium not only enhances the density of nucleate sites, but also facilitates the coalescence among the InN islands. The free energy calculations reveal that the pre-deposited indium atoms preferentially react with NH and N radicals after NH3 introduction, which leads to the formation of InN on the sapphire surface. The preferentially formed InN is then supposed to be responsible for the above phenomena.