Improved Surface-Enhanced-Raman Scattering Sensitivity Using Si Nanowires/Silver Nanostructures by a Single Step...

Area of Science:

• Nanotechnology
• Materials Science
• Spectroscopy

Background:

• Surface-Enhanced-Raman-Scattering (SERS) spectroscopy requires highly sensitive substrates.
• Silicon nanowires (SiNWs) offer a promising platform for SERS substrate development.
• Metal Assisted Chemical Etching (MACE) is a method for fabricating nanostructured materials.

Purpose of the Study:

• To develop highly sensitive SERS substrates using SiNWs decorated with silver nanostructures.
• To compare the SERS performance of silver aggregates versus dendritic structures on SiNWs.
• To investigate the fabrication of these nanostructured substrates via single-step MACE.

Main Methods:

• Fabrication of SiNWs decorated with silver nanostructures using single-step MACE on p-type Si substrates.
• Controlled formation of silver aggregates and dendrites by adjusting immersion times in AgNO3/HF and HNO3 solutions.
• Testing SERS activity using Rhodamine 6G (R6G) as an analyte.

Main Results:

• SiNWs decorated with silver aggregates and dendrites were successfully synthesized.
• Silver aggregate substrates exhibited a lower limit of detection (LOD) down to 10^-13 M for R6G.
• SERS enhancement factors ranged from 10^5 to 10^10, indicating high sensitivity.

Conclusions:

• Single-step MACE is an effective method for creating sensitive SERS substrates.
• Silver aggregates on SiNWs demonstrate superior SERS performance, including lower LOD and better uniformity, compared to dendritic structures.
• The developed substrates show significant potential for sensitive analytical applications.