Localized suppression of longitudinal-optical-phonon-exciton coupling in bent ZnO nanowires

Using confocal micro-Raman and photoluminescence spectroscopy, we studied bending effects on optical properties of individual ZnO nanowires. Raman spectroscopy shows that local tensile strain can be introduced by bending the nanowire. The strain is expected to reduce the band gap on the bent part and modify the local phonon-exciton interaction. The corresponding micro-photoluminescence spectra indicate local suppression of the longitudinal-optical (LO) phonon-exciton interaction, which is determined by the intensity ratio of the second-order LO-phonon replica of the free exciton (FX-2LO) to the first-order process (FX-1LO). Our results may provide insight into the modulation of local electrical and optical properties by deforming the nanostructures.