X-ray absorption near-edge structure ͑XANES͒, extended x-ray absorption fine structures ͑EXAFS͒, and photoluminescence measurements were used to elucidate the microstructural and photoluminescence properties of ZnO nanowires ͑ZnO-NWs͒ 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 2 O 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-4f transition of Eu ions in the Eu 2 O 3-like surface layer.

No abstract