Nanoscale epitaxial growth of GaN on freestanding circular GaN grating

Freestanding circular GaN gratings are fabricated on a GaN-on-silicon substrate, and epitaxial growth of GaN is subsequently conducted on the prepared GaN template by molecular beam epitaxy growth. With the assistance of circular GaN gratings, the surface diffusion is improved and thus, the selective growth of GaN takes place. Epitaxial circular gratings with InGaN/GaN multiple quantum wells are generated with self-organized lateral facets and demonstrate the promising photoluminescence performances. This work provides a feasible approach to produce integrated GaN-Si devices by a combination of fast atom beam etching of GaN, silicon micromachining and epitaxial growth of GaN.