Comparison study of N- and In-polar {0001} InN layers grown by MOVPE

We compare InN layers grown directly on c -plane (0001) sapphire and on (0001) GaN templates using metal-organic vapor phase epitaxy. InN grown on nitridated c -plane sapphire showed N-polarity, while InN grown on c -plane GaN templates showed In-polarity. N-polar and In-polar InN layers showed different surface morphology and crystallinity. N-polar InN was smoothest when grown at higher growth temperatures, while In-polar InN was smoothest at intermediate growth temperatures. Growth mode of the N-polar InN on sapphire is Frank-Van der Merwe, while growth mode of the In-polar InN on GaN templates is Volmer-Weber. Electrical properties were similar for both layers. Lowtemperature photoluminescence of In-polar InN layers is shifted to higher energies most likely due to biaxial compressive stresses. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)