Surface optical phonon modes in ternary aligned crystalline InGaN/GaN multi-quantum-well nanopillar arrays

The optical properties of focused ion beam-engraved, perfectly aligned and spatially controlled multi-quantum-well (MQW) InGaN/GaN nanopillars were investigated. Crystalline MQW nanopillars with a diameter of 30-95 nm and high aspect ratios (7: 1-16: 1) showed a maximum of three-fold enhancement in emission intensity per unit active area. A light-emitting contour map of Taiwan is drawn with a nanopillar structure to demonstrate the site control of the technique adopted in the present study. Raman scattering studies were used to characterize the newly created surfaces. Unknown peaks in GaN and InGaN nanostructures are identified for surface optical (SO) phonon modes with proper assignments of wave vectors using multiple excitations, and the SO mode for the ternary phase is reported for the first time.