Nanoforest-based SERS sensor fabricated using a maskless process for detecting chemical and pathogen

Nanoscale silicon forest-based surface enhanced Raman spectroscopy (SERS) sensor was fabricated using a simple maskless Bosch process method. Silicon nanoforest was further coated with gold and grafted with silver-plate nanoparticles. Fabricated SERS sensor was then utilized to detect 106 CFU/ml Escherichia coli (E. coli), achieving Raman signal enhancement of ~ 106. Furthermore, by detecting a mixture of R6G and E. coli, multiplexed detection was successfully demonstrated. A series of numerical simulation was performed to study the enhancement factor of the fabricated SERS sensor, matching the experimental results. Due to the simplicity of the fabrication process and its cost-effectiveness, this type of nanoforest SERS sensor is a promising cartridge-type device for a hand-held Raman spectrometer microsystem for both qualitative and quantitative detection of bacterial/viral pathogens in the field of food microbiology.