Differences in nucleation and properties of InN islands formed using two different deposition procedures

The initial stages of metalorganic chemical vapor deposition of InN have been investigated using two different growth procedures: growth of InN over a GaN buffer layer in one continuous run and growth of InN on a pre-deposited GaN template. While the growth conditions and material quality of the GaN underlying layers are nominally the same, characterization by AFM, X-ray diffraction and PL spectroscopy reveals significantly different material properties of InN islands formed using the two procedures and suggests a different path of evolution during the initial stages of growth. In particular, InN islands grown on a pre-deposited GaN template seem to nucleate directly on the GaN template and are 5 times larger in volume and 2 times lower in surface density as compared with InN growth in one continuous run with the GaN underlying layer. Our studies suggest that the Ga incorporation into the InN during the growth on a GaN buffer layer in one continuous run plays a significant role in altering InN growth mechanisms and material properties.