Oblique angle transmission spectroscopic measurements on InGaN/GaN dot-in-a-wire heterostructures*

Nearly defect-free GaN nanowires embedded with intrinsic InGaN quantum dots presents the opportunity to control the surface and longitudinal optical phonons modes which are dependent on the nanowire fill-factor, doping densities of the nanowires and the presence of InGaN dots. These effects are observed using the oblique angle transmission infrared spectroscopy. The tunable optical properties of these nanostructures show potential for phonon assisted photodetectors whose spectral responses can be tailored by varying a combination of these three parameters. The optical anisotropy along the growth ($c$-) axis of the GaN nanowire introduces the polarization agility seen in the transmission spectra, which can lead to polarization agile photodetectors.