Well Controlling of Plasmonic Features of Gold Nanoparticles on Macro Porous Silicon Substrate by HF Acid Concentration

in this work, we fabricated an efficient macroporous silicon/gold nanoparticles (macro psi/aunps) hybrid structure and how well controlling of plasmonic features on macro psi/aunps employs them for highly sensitive detection of the very low concentration of cyanine (cy) dyes molecules. macro-psi was synthesized on n-type si wafer with 3–10 ω. cm resistivity and 100 orientation using photo electro chemical etching (pece) process with630 nm illumination wavelength and 30 mw/cm2 illumination intensity. the macropsi /aunps hybrid structure substrates were prepared by simple and quick dipping process of macropsi in tetrachloroauric gold solution haucl4 with different concentrations of (10−2  m, 10−2 m diluted in 2.9  m of hf, 5 × 10−3 m, and 5 × 10−3 m diluted in 2.9 m of hf). efficient surface-enhanced raman scattering (sers) signals was obtained from macropsi/aunps substrates for cy dye concentration of about 10−6 and 10−10 m. the detection method is dependent on a nanoparticles sizes process through controlling the concentration in a haucl4 solution. higher sers signal was found for sample with lower salt concentration of 5 × 10−3 m diluted in hf. the enhancement factors (ef) of raman’s signal increased four orders of magnitude by diluting the salt concentration. the values of ef in the range of 0.8 × 103−0.72 × 107 were obtained by controlling the salt concentration from 10−2 to 5 × 10−3 diluted in hf acid.