= Solution
In \b[<selective-area epitaxy>], precursors supplied by <metal-organic vapour-phase epitaxy> incorporate on exposed crystalline InP through patterned openings in a silicon-nitride mask. Epitaxial facet-dependent incorporation and surface <diffusion> select axial and radial <growth rates>. Advantages include lithographic position and pitch control, an epitaxial orientation relationship and the absence of a foreign metal <catalyst>. Limitations include mask patterning, selective <nucleation> requirements, facet-dependent composition, loading and pitch effects, and unwanted radial growth.
In \b[<vapour-liquid-solid growth>], precursors decompose and supply material to a liquid <catalyst> droplet; <supersaturation> drives precipitation at the liquid-solid interface. Droplet size can control wire diameter and enable high <aspect ratios>. Limitations include possible <catalyst> contamination, droplet stability and coarsening, composition memory at heterointerfaces, and restrictions from the <catalyst> <phase diagram>. Patterned <catalyst> placement can also control position, so positional ordering is not exclusive to selective-area growth. Conversely, selective-area wires are not automatically free of taper or compositional interfaces.<Efficient Green Emission from Wurtzite AlInP Nanowires by L. Gagliano and others>[Selective-area growth and composition-dependent <nanowire> structure]{ref}
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