InN metalorganic vapour phase epitaxy and ellipsometric characterisation

The morphology of InN layers grown directly on sapphire is strongly affected by the large lattice mismatch; epitaxial layers exceeding a thickness of 150 nm were found to partially bulge and peel off, regardless of different growth parameters. In-situ spectroscopic ellipsometry was crucial to identify the occurring process. Parasitic nucleation is another issue in InN MOVPE growth, but we showed that this can be controlled with slightly higher growth temperatures. The pseudodielectric function of InN was measured by means of SE in the range from 0.5 to 6.4 eV and the dielectric function of InN was calculated with an optical model in the bandgap region, determining a bandgap energy of 1.0 eV at room temperature for InN grown by MOVPE. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)