Optical Properties of Monodispersed AlGaN Nanowires in the Single-Prong Growth Mechanism

Abstract

Growth of monodispersed AlGaN nanowires of ternary wurtzite phase is reported using the chemical vapor deposition technique in the vapor–liquid–solid process. The role of distribution of Au catalyst nanoparticles on the size and shape of AlGaN nanowires is discussed. These variations in the morphology of the nanowires are understood invoking Ostwald ripening of Au catalyst nanoparticles at high temperature followed by the effect of single and multiprong growth mechanism. Energy-filtered transmission electron microscopy is used as an evidence for the presence of Al in the as-prepared samples. A significant blue shift of the band gap, in the absence of quantum confinement effect in the nanowires with diameter ∼100 nm, is used as a supportive evidence for the AlGaN alloy formation. Polarized resonance Raman spectroscopy with strong electron–phonon coupling along with optical confinement due to the dielectric contrast of nanowire with respect to that of surrounding media are adopted to understand the crystall...