Structural properties of InN thin films grown with variable growth conditions on GaN/Al2O3 by plasma-assisted MBE

The structural characteristics of compact and columnar InN films grown by molecular beam epitaxy oil GaN templates are investigated by transmission electron microscopy. Compact mode of growth is favoured at low substrate temperatures, below 500 degrees C, and by the introduction of an InN nucleation layer prior to the InN epilayer growth. Improved quality compact InN films, having threading dislocations with densities on the order of 10(9) 10(10) cm(-2), are achieved by using high In/N flux ratios. Compact films generally exhibit higher in-plane lattice constant values than columnar ones and, consequently, higher densities of InN/GaN interfacial misfit dislocations.