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应用气相传输法制备了氧化锌纳米线和具有六方对称截面的纳米棒,利用电子扫瞄显微镜,X-射线衍射仪等进行形貌与结构表征。室温下,用355nm激光脉冲,以260 W/cm2相同光强激励条件,分别测量其光致发光(PL)谱,在棒状样品中发现393nm有发光峰,而线状样品是在382nm处。二者相比,棒状样品的紫光波段自发辐射光强增加、频谱展宽、中心波长红移和绿光波段辐射被显著抑制。基于半导体材料的能带理论、激子复合发光理论和费米黄金定则等,对样品PL谱差异原因进行理论分析,结果表明上述现象源于棒状样品中回音壁模谐振腔(WGMRs)的自发辐射增加。利用强激励条件下样品光致发光谱,验证了实验结果与理论分析结果较好吻合。
ZnO nanowires and nanorods with hexagonal symmetry cross section were prepared by gas phase transport method. The morphology and structure were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photoluminescence (PL) spectra were measured at 355 W with 355 W laser pulses at 260 W / cm2, respectively. The luminescence peaks at 393 nm were observed in the rod samples and at 382 nm in the linear samples. Compared with the two samples, the light intensity of the spontaneous emission in the violet band of the rod-shaped sample increased, the spectral broadening, the red shift of the center wavelength and the emission of the green band were significantly suppressed. Based on the band theory of semiconductor materials, the exciton recombination luminescence theory and the Fermi gold rule, the reason of the PL spectrum differences in the samples is analyzed theoretically. The results show that the above phenomenon originates from the self-generation of WGMs Radiation increased. The photoluminescence (PL) spectra of samples under strong excitation were used to verify that the experimental results agree well with the theoretical analysis.