Photoluminescence and Raman Studies of Annealed ZnO Nanostructures

Abstract:

The influence of annealing on the optical properties of as-grown ZnO nanostructures prepared in pellets has been investigated by photoluminescence (PL) and Raman spectroscopy. The annealing temperatures of ZnO nanostructure at 600°C, 650°C and 700 °C were conducted in oxygen (O2) and nitrogen (N2) ambient. The near band edge emission (NBE) of samples recorded in the PL spectra demonstrates significant changes on optical signal whereby the NBE is redshifted after O2 annealed and became slightly higher in N2 annealed. Apart from that, weak green luminescence (GL) namely deep band emission (DBE) is observed centre at 532.95 nm (2.23 eV) and 511.00 nm (2.42 eV) for annealed in O2 and N2 respectively, whereas lower DBE observed in as-grown ZnO. On the other hand, Raman shift reveal the phonon mode of the ZnO nanostructures and the E2 (high) mode were downshifted as annealed in O2 ambient, and upshifted in N2 ambient. The downshift and upshift of the E2 (high) mode are correlated to tensile and compressive stress. Moreover the crystallite sizes were calculated from FWHM of XRD and TEM microscopy reveals the nanoplates structure of ZnO nanostructures.

• Periodical: Advanced Materials Research (Volume 501)
• Pages: 179-183
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.501.179
• Online since: April 2012
• Authors: Siti Khadijah Mohd Bakhori, Chuo Ann Ling, Shahrom Mahmud
• Keywords: Annealing, Photoluminescence (PL), Raman Spectroscopy, Zinc Oxide (ZnO)

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