Structure evolution and SERS activation of cuprous oxide microcrystals via chemical etching

The morphology, composition, and structure of semiconductor nanomaterials play important roles in tuning their unique physical and chemical properties for a variety of applications. We report a facile chemical method to etch cuprous oxide microcrystals which resulted in excellent performance in surface-enhanced Raman scattering (SERS). Microscopic and spectroscopic tools were utilized to investigate the cuprous oxide structures with the chemical etching, as well as the assessment of the SERS sensitivity. The increasing SERS sensitivity can be attributed to the generation of Raman hot spots related to the etching-induced rough surface, sharp tips and edges, as well as the strong chemical interactions between the probe molecules and the SERS substrates. Our work introduced a simple method to modify the semiconductor nanomaterials and induce SERS activity, thus expanding the application area of cuprous oxide microcrystals.