Gold nanoparticles (Au NPs) were synthesized by co-deposition of RF-sputtering and RF-PECVD fromacetylene gas and Au target on the carbon nanotubes (CNTs). The CNTs were prepared by thermal chem-ical vapor deposition (TCVD) and Pd nanoparticles catalyst. TEM image shows that high-density anduniform distribution of Au NPs were grown on the CNTs. XRD analysis indicates that Au NPs have fcccrystal structure and CNTs have a good graphite structure. Raman spectroscopy results suggest that oursample includes double-walled CNTs. It is resulted that intensity of D-band reduces and G-band inten-sity raises and radial breathing mode (RBM) is changed by immobilizing of Au NPs on the CNTs. Ramanresults that the free electrons on the CNTs increase by immobilizing of Au NPs. Also localized surface plas-mon resonance (LSPR) peak of Au NPs has red-shift and broadens when it is immobilized on the CNTs.The change in LSPR peak rises from decreasing of local electrons density on the Au NPs surface. Ramanand LSPR spectroscopy suggest that there are charge transferring and chemical bonds between Au NPsand CNTs. We applied the prepared sensor chips of Au NPs@CNTs to detect DNA primer at femtomolarconcentration based on the LSPR technique.
