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Controlled growth of In-rich InGaN nanowires/nanorods (NRs) has long been considered as a very challenging task. Here, we present the first attempt to fabricate InGaN NRs by selective area growth using hydride vapor phase epitaxy. It is shown that InGaN NRs with different indium contents up to 90% can be grown by varying the In/Ga flow ratio. Furthermore, nanowires are observed on the surface of the grown NRs with a density that is proportional to the Ga content. The impact of varying the NH3 partial pressure is investigated to suppress the growth of these nanowires. It is shown that the nanowire density is considerably reduced by increasing the NH3 content in the vapor phase. We attribute the emergence of the nanowires to the final step of growth occurring after stopping the NH3 flow and cooling down the substrate. This is supported by a theoretical model based on the calculation of the supersaturation of the ternary InGaN alloy in interaction with the vapor phase as a function of different parameters assessed at the end of growth. It is shown that the decomposition of the InGaN solid alloy indeed becomes favorable below a critical value of the NH3 partial pressure. The time needed to reach this value increases with increasing the input flow of NH3, and therefore the alloy decomposition leading to the formation of nanowires becomes less effective. These results should be useful for fundamental understanding of the growth of InGaN nanostructures and may help to control their morphology and chemical composition required for device applications. [ABSTRACT FROM AUTHOR]

We report for the first time on the hydride vapor phase epitaxy (HVPE) growth of long (26 μm) InAs nanowires on Si(111) substrate grown at a standard rate of 50 μm h−1. The nanowires grow vertically along the (111)B direction and exhibit a well faceted hexagonal shape with a constant diameter. The effect of the experimental parameters, growth temperature and III/V ratio, is investigated. The thermodynamic and kinetic mechanisms involved during the growth of such long nanowires are identified. It is demonstrated that growth occurs through direct condensation of InCl and As4/As2 gaseous species. Dechlorination of adsorbed InCl molecules is the limiting step at low temperature. Structural analysis through high resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field (HAADF) imaging was performed. The high As4 partial pressure of the HVPE environment induces the presence of both wurtzite and zinc-blende phases. The results emphasize the potential of the low cost HVPE technique for the monolithic integration of arrays of long InAs nanowires on silicon. [ABSTRACT FROM AUTHOR]

GaNnanowires with exceptional lengths are synthesized by vapor–liquid–solidcoupled with near-equilibrium hydride vapor phase epitaxy techniqueon c-plane sapphire substrates. Because of the highdecomposition frequency of GaCl precursors and a direct supply ofGa through the catalyst particle, the growth of GaN nanowires withconstant diameters takes place at an exceptional growth rate of 130μm/h. The chemical composition of the catalyst droplet is analyzedby energy dispersive X-ray spectroscopy. High-resolution transmissionelectron microscopy and selective area diffraction show that the GaNnanowires crystallize in the hexagonal wurzite structure and are defect-free.GaN nanowires exhibit bare top facets without any droplet. Microphotoluminescencedisplays a narrow and intense emission line (1 meV line width) associatedto the neutral-donor bound exciton revealing excellent optical propertiesof GaN nanowires. [ABSTRACT FROM AUTHOR]