Silver coated porous silicon used as a surface enhanced Raman scattering (SERS)-active substrate for methylene blue detection

  • Lorenzo Lopez, Jr Material Science and Engineering Program, University of the Philippines Diliman
  • Maria Angela Faustino Material Science and Engineering Program, University of the Philippines Diliman
  • Arven Cafe National Institute of Physics, University of the Philippines Diliman
  • Christopher Jude Vergara Material Science and Engineering Program, University of the Philippines Diliman
  • Horace Andrew Husay National Institute of Physics, University of the Philippines Diliman
  • Joybelle Lopez Material Science and Engineering Program, University of the Philippines Diliman
  • Catherine Tugado Material Science and Engineering Program, University of the Philippines Diliman
  • Arnel Salvador National Institute of Physics, University of the Philippines Diliman
  • Elmer Estacio National Institute of Physics, University of the Philippines Diliman
  • Armando Somintac National Institute of Physics, University of the Philippines Diliman

Abstract

Porous silicon (PSi) coated with silver (Ag) was used as surface-enhanced Raman scattering (SERS)-active substrate for detection of methylene blue (MB). The PSi was formed via electrochemical etching of silicon (Si) wafer in a solution of hydrofluoric acid and ethanol. Porosities of 55% and 63% of PSi were fabricated using anodic current of 5 mA and 10 mA for 1000 s and 625 s respectively. These were immersed into Ag nitrate solution with 0.01 molar concentration for Ag coating. An-order-of-magnitude enhancement of Raman signal of MB was observed using SERS-active substrate with 63% PSi’s porosity. This suggests that more Ag were deposited on the high-porosity SERS-active substrate which resulted to Raman signal amplification due to surface plasmon resonance. Another factor that might cause such enhancement is the charge-transfer between the MB molecules and the substrate. Different molar concentrations of MB were synthesized. The MB molar concentration dependent studies showed that the substrate based on Ag coated PSi is sensitive up to 10-7 M.

Published
2017-05-25
How to Cite
[1]
L. Lopez, M. A. Faustino, A. Cafe, C. J. Vergara, H. A. Husay, J. Lopez, C. Tugado, A. Salvador, E. Estacio, and A. Somintac. Silver coated porous silicon used as a surface enhanced Raman scattering (SERS)-active substrate for methylene blue detection, Proceedings of the Samahang Pisika ng Pilipinas 35, SPP-2017-PA-30 (2017). URL: https://paperview.spp-online.org/proceedings/article/view/259.
Section
Poster Session A (Materials Science, Instrumentation, and Photonics)