Growth of large-scale vertically aligned GaN nanowires and their heterostructures with high uniformity on SiO_x by catalyst-free molecular beam epitaxy

The catalyst-free molecular beam epitaxial growth of GaN nanowires and their heterostructures on a SiO_x template is studied in detail. It was found that by optimizing the growth temperature, highly uniform and vertically aligned GaN nanowires and InGaN/GaN heterostructures with excellent optical properties can be obtained on a SiO_x template in a large-scale. This work provides an entirely new avenue for GaN nanowire based optoelectronic devices.