Well-ordered and vertically aligned InN nanorods with high aspect ratios are synthesized by hydride vapor phase epitaxy (HVPE) using the selective area growth (SAG) approach. The growth occurs through the apertures of a SiN_x masked Ga-polar GaN/c-Al₂O₃ template for adjusted growth temperature and V/III ratio. The nanorods exhibit a hexagonal shape without any rotation around the growth axis. The wurtzite structure and the high crystalline quality of InN nanorods are confirmed by X-ray diffraction (XRD) as well as by high-resolution transmission electron microscopy (HR-TEM). Only few stacking faults are identified at the bottom part of the nanorods. Photoluminescence (PL) displays an emission peak centered at 0.77 eV which agrees with the band gap of InN. These promising achievements, which go far beyond the existing InN growth limitations, pave the way towards the integration of pure InN in future devices.

Homogenous InGaN nanowires with a controlled indium composition up to 90% are grown on GaN/c-Al ₂ O ₃ templates by catalyst-free hydride vapor phase epitaxy using InCl ₃ and GaCl as group III element precursors. The influence of the partial pressures on the growth rate and composition of InGaN nanowires is investigated. It is shown how the InN mole fraction in nanowires can be finely tuned by changing the vapor phase composition. Thermodynamic calculations are presented that take into account different interconnected reactions in the vapor phase and show a good agreement with the compositional data. Energy dispersive x-ray spectroscopy profiles performed on single nanowires show a homogenous indium composition along the entire nanowire length. X-ray diffraction measurements performed on nanowires arrays confirm these data. High-resolution transmission electron microscopy analysis shows the wurtzite crystal structure with a reduced defect density for InGaN nanowires with the highest indium content.