Integrated photonics on silicon with wide bandgap GaN semiconductor

We report on GaN self-supported photonic structures consisting in freestanding waveguides coupled to photonic crystal waveguides and cavities operating in the near-infrared. GaN layers were grown on Si (111) by metal organic vapor phase epitaxy. E-beam lithography and dry etching techniques were employed to pattern the GaN layer and undercut the substrate. The combination of low-absorption in the infrared range and improved etching profiles results in cavities with quality factors as high as ∼5400. The compatibility with standard Si technology should enable the development of low cost photonic devices for optical communications combining wide-bandgap III-nitride semiconductors and silicon.