Epitaxial MOVPE growth of highly c-axis oriented InGaN/GaN films on ZnO-buffered Si (111) substrates

InGaN/GaN layers were grown on ZnO-buffered Si (111) substrates by metalorganic vapour phase epitaxy (MOVPE). The dissociation of ZnO observed during conventional MOVPE growth of InGaN/GaN was combated through the use of a low pressure/temperature MOVPE approach with N-2 as a carrier gas and dimethylhydrazine added to the ammonia (nitrogen precursor) in order to enhance the concentration of atomic nitrogen at relatively low temperature. Electron Microscopy of cross-sections, High Resolution X-Ray Diffraction (HR-XRD), secondary ion mass spectroscopy and cathodoluminescence studies suggested that single phase wurtzite InGaN layers with between about 17.5 and 21.5% indium were grown epitaxially, with no evidence of back-etching of the ZnO templates. HR-XRD revealed highly pronounced c-axis texture for both the InGaN/GaN and ZnO. Immersion in dilute nitric acid dissolved the ZnO such that the InGaN/GaN could be lifted-off from the substrate.