Optical characterization of ZnO nanorods

• Main Authors: Huang-Wei Jhou, 周黃蔚
• Other Authors: Ching-Hwa Ho
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/6meqg8

碩士 === 國立東華大學 === 材料科學與工程學系 === 95 === The band-edge excitonic transitions of vertical- and lateral-growth ZnO nanorods on sapphire as well as the vertical-growth ZnO nanorods on Si have been characterized using thermoreflectance (TR) and photoluminescence(PL) measurements in the temperature range between 30 and 300 K. The TR spectra of the nanorods with the largely {0001} planes show considerable difference in energy and lineshape with respect to those of the other sample with the largely side planes of {10 0}. The experimental TR result at each temperature clearly indicates the band-edge excitons(A, B, and C) measured from the largely {0001} planes of the rods are lower in energy with respect to those obtained from the other sample dominated by the side planes of {10 0}. Optical anisotropy in the transition amplitudes of the TR spectra for the vertical- and lateral-growth ZnO nanorods is found. Temperature dependence of transition energies of the ZnO nanorods is analyzed. The optical anisotropic behavior for the vertical- and lateral-growth ZnO nanorods is discussed. The PL spectra show the A、B transitions are the dominant luminescence excitons in the ZnO nanorods. Besides, ZnO/Si and ZnO/Sapphire have some defect enrgy levels inside the crystals. The defect levels may result in a strong luminescence of ~1.6eV present in the PL spectra of both ZnO/Si and ZnO/Sapphire samples.