also crystallized in the same hexagonal structure. The average crystallite size was estimated from the most intense XRD peak [(1 0 1)] to be about 33 nm by using Scherrer's formula [23]. Fig. 3 shows the Raman spectra of ZnO nanofibers annealed at 500 1C and 550 1C for 90 min. The strong Raman peak near 437 cm 1 corresponds to Eh2igh phonon mode of wurtzite ZnO and the peak located at 385 cm 1 corresponds to A1-TO mode. The peak located at $581 cm 1 (E1-LO) has been attributed to O-vacancy defects present