A nanoforest-based SERS sensor fabricated by Bosch process for multiplexed chemical detection

A new simple maskless fabrication method based on room temperature Bosh process was developed to fabricate silicon nanoforest. After being coated with a layer of Au, the Au-coated silicon nanoforest was converted into a surface-enhanced Raman spectroscopy (SERS) substrate. To further enhance SERS signals, the Au-coated silicon nanoforest was grafted with silver-plate nanoparticles (AgNPs). The SERS substrate was used to detect Escherichia coli as a model strain at 10
⁶
CFU/mL, and a Raman signal enhancement factor of ∼10
⁶
was achieved without any optimization of the SERS substrate. Multiplexed detection was demonstrated through differentiating R6G and E. coli on the same substrate. Given the simplicity and low-cost of the preparation scheme, and the high enhancement efficiency of this nanoforest-based SERS substrate, it can be potentially used in the field of diagnostic microbiology for the label-free detection of bacterial and viral pathogens, and it is also suitable for detecting and analyzing mixtures of compounds to determine their compositions.