“…[1][2][3] SERS can serve as a highly sensitive probe for trace detection of chemical and biological molecules up to a single molecule level, [4][5][6] and a powerful technique that can be applied in food safety, environmental and biomedical sciences. [7][8][9] To date, various SERS substrates have been reported, such as metal nanoparticle assemblies, [10][11][12][13] roughened metal substrates, [14][15][16][17] porous or holey substrates [18][19][20] and even semiconductor-based substrates. [21][22][23][24] However, SERS substrates should be reproducible, facile for fabrication, highly sensitive, and site-independent of "hot spots", while the great majority of above-mentioned substrates require relatively complicated and cost-ineffective manipulations.…”