Asymmetric Broadening of A1(LO) Raman Peak of Nanocrystal Aggregated GaN Nanowires

Novel GaN nanowires were synthesized by a chemical vapor deposition (CVD) method. The morphology and structure of the nanowires were investigated by SEM, XRD and Raman spectra. Results show that GaN nanowires are formed by aggregated GaN nanocrystals, which is due to the non-uniform precipitation of GaN from catalyst droplet. An asymmetric broadening and shifting to lower frequency of A1(LO) peak are observed in the Raman spectra, which mainly contribute to the Fano interference between scattering from the k=0 optic phonon and electronic continuum scattering from laser-induced electrons.