Figure 3

a Confocal Raman spectra of ZnONW; and b ZnO powders. The main peak at 435.8 cm⁻¹ is assigned to the E₂ (high frequency) optical phonon mode of ZnO. The inset shows an optical image of a single isolated ZnONW for confocal Raman scattering. The Lorentzian curves fitting results show that the values of peaks and full width half maximum (FWHM) are 435.8(2) and 9.51(1) cm⁻¹ for a single ZnONW and 438.2(1) and 9.12(2) cm⁻¹ for the ZnO powder, respectively