Epitaxial Catalyst-Free Growth of InN Nanorods onc-Plane Sapphire
1 Harvard University, Cambridge, MA, 02138, USA
2 Ben Gurion University, Beer Sheva, Israel
3 University of Houston, Houston, TX, 77004, USA
Nanoscale Research Letters 2009, 4:532-537 doi:10.1007/s11671-009-9276-zPublished: 27 February 2009
We report observation of catalyst-free hydride vapor phase epitaxy growth of InN nanorods. Characterization of the nanorods with transmission electron microscopy, and X-ray diffraction show that the nanorods are stoichiometric 2H–InN single crystals growing in the  orientation. The InN rods are uniform, showing very little variation in both diameter and length. Surprisingly, the rods show clear epitaxial relations with thec-plane sapphire substrate, despite about 29% of lattice mismatch. Comparing catalyst-free with Ni-catalyzed growth, the only difference observed is in the density of nucleation sites, suggesting that Ni does not work like the typical vapor–liquid–solid catalyst, but rather functions as a nucleation promoter by catalyzing the decomposition of ammonia. No conclusive photoluminescence was observed from single nanorods, while integrating over a large area showed weak wide emissions centered at 0.78 and at 1.9 eV.