Preparation and Characterization of Zn_1-NiO Nanoparticles: Application as a SERS Substrate

In this paper, the study of the Zn1-xNixO (x = 0, 0.01, 0.03, 0.05) nanoparticles as SERS active substrate has been reported. The structural, morphological and optical studies are carried out by XRD, XPS, SEM, UV-vis and Raman spectroscopy. The XRD spectra indicate that the four Zn1-xNixO nanoparticles (x = 0, 0.01, 0.03, 0.05) are all single wurtzite structure. XPS study further demonstrates that Ni atoms are successfully doped into ZnO lattice. We have observed strong SERS signals when the 4-mercaptobenzoic acid used as the probe molecules. An interesting phenomenon is that an appropriate amount of the Ni atoms doping can enhance the SERS spectrum, and the maximum SERS intensity appeared when the Zn1-xNixO (x = 0.03) as the SERS active substrate, and we ascribe the SERS mechanism to the charge-transfer mechanism. The energy levels caused by the surface defects of ZnO NPs by Ni doping have influence on the charge-transfer process and have benefit for the SERS performance.