Infrared and Raman-scattering studies in single-crystalline GaN nanowires

Infrared and Raman-scattering studies of high-purity and -quality GaN nanowires are presented. The nanosize dependences of the peak shift and the broadening of the four first-order Raman modes agree with those calculated on the basis of the phonon confinement model. Additionally, the appearance of one Raman mode at ∼254 cm−1 is attributed to zone-boundary phonon activated by surface disorders and finite-size effects. Moreover, the Raman-scattering intensities of certain phonons show a different resonantly enhanced behavior, which can be used to verify the information on the electronic structures and the electron–phonon interaction in GaN nanowires.