Europium doping induced symmetry deviation and its impact on the second harmonic generation of doped ZnO nanowires
Europium doping induced symmetry deviation and its impact on the second harmonic generation of doped ZnO nanowires
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DOI：
10.1088/0957-4484/25/22/225202
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发表时间：
2014-06-06
期刊：
影响因子：
3.5
通讯作者：
Fujii, Minoru
中科院分区：
文献类型：
--
作者：
Dhara, Soumen;Imakita, Kenji;Fujii, Minoru
In this work, we investigated the effects of europium doping on the second harmonic generation (SHG) of ZnO nanowires (NWs). A non-monotonic enhancement in the SHG is observed with the increase of the europium concentration. Maximum SHG is observed from the 1 at.% europium doped ZnO NWs with an enhancement factor of 4.5. To understand the underlying mechanism, the effective second order non-linear coefficient (d(eff)) is calculated from the theoretical fitting with consideration of the absorption effect. Microstructural characterization reveals the structural deformation of the ZnO NWs caused by europium doping. We estimated the deviation in the crystal site symmetry around the Eu3+ ions (defined as the asymmetric factor) from photoluminescence measurement and it is found to be strongly correlated with the calculated deff value. A strong linear dependence between the magnitudes of d(eff) and the asymmetric factor suggests that deviation in the local site symmetry of the ZnO crystal by europium doping could be the most probable origin of the observed large second order nonlinearity.
