Determination of the microstructure of Eu-treated ZnO nanowires by x-ray absorption

摘要

X-ray absorption near-edge structure (XANES), extended x-ray absorption fine structures (EXAFS), and photoluminescence measurements were used to elucidate the microstructural and photoluminescence properties of ZnO nanowires (ZnO-NWs) that had been treated with Eu by thermal diffusion. The O K- and Eu L_3-edge XANES and EXAFS spectra at the Zn K- and Eu L_3-edge verified the formation of Eu_2O_3-like layer on the surface of ZnO-NWs. X-ray diffraction, XANES and EXAFS measurements consistently suggest the lack of substitutional doping of Eu ions at the Zn ion sites in the interior of ZnO-NWs. The clear sharp and intense emission bands in the range 610-630 nm of Eu-treated ZnO-NWs originated from the intra-4/ transition of Eu ions in the Eu_2O_3-like surface layer.