Top-down fabrication for III-nitride nanophotonics

III-nitride based nanostructures have gained interest as nanoscale light sources in the UV to visible wavelengths. Here we present a top-down approach to enable vertical, high aspect ratio III-nitride-based nanowires with controllable height, pitch, and diameter. Additionally, through the use of orientation-dependent etch rate measurements, the cross-sections of such nanostructures can be predicted and controlled, which can allow for the manipulation of optical properties. The fabrication and lasing characteristics of GaN-based nanowires fabricated by this approach will be presented, along with schemes for single optical mode selection, polarization control, beam shaping, and wavelength tuning. Finally, we present a new method for the etching of size-controlled InGaN quantum dots (QDs) using quantum size effects.