Origin of broad luminescence from site-controlled InGaN nanodots fabricated by selective-area epitaxy

We investigated the origin of broad luminescence observed from an array of site-controlled InGaN nanodots grown by selective area epitaxy (SAE). Epitaxially grown site-controlled nanodots with lateral dimensions <50 nm and an array density of 10¹⁰ cm^-2 have been studied. During the nanoscale SAE, incorporation of adatoms from the SiO₂ mask has greater relative importance, resulting in a non-uniform growth profile. This non-uniform growth profile leads to significant broadening of the InGaN nano-heterostructure luminescence. Later in the SAE process, an orientation-dependent growth rate coalesces various crystal planes and transforms these nanostructures into a more uniform array.