Structural, Electrical and Raman Characterization of Porous Silicon Based SERS Substrate

Surface-Enhanced Raman Spectroscopy (SERS) is a highly sensitive and specific technique with broad applications, but its effectiveness is heavily dependent on the quality of the SERS substrate used. This study's primary goal is to fabricate a SERS substrate that can detect low-concentration analytes, particularly for non-invasive salivary-based disease detection. This research investigates the structural, electrical, and Raman properties of porous silicon (PSi) fabricated from different types of silicon wafers, varying in dopant type and resistivity, to serve as the base for the SERS substrate. PSi samples were produced using a direct current (DC) photo-assisted electrochemical etching method. FESEM images revealed that n-type silicon produces larger pores compared to p-type silicon. The I-V curves demonstrated better conductivity in p-type silicon, particularly those with low resistivity values, while the best Raman efficiency was observed in n-type silicon. The inclusion of silver nanoparticles (AgNPs) significantly enhanced the detection capabilities of Rhodamine 6G (R6G). These findings emphasize the importance of dopant type and resistivity in influencing the structural, electrical, and optical properties of PSi, providing valuable insights for optimizing PSi characteristics as SERS substrates. This research advances SERS technology for more sensitive molecular detection in a variety of fields.