Fig. 1. Vacancy-induced SERS-active semiconductor substrates. (a) SERS spectra of R6G on pristine and Ar/H2-treated W18O49. Reproduced with permission from ref. 26. Copyright 2015, Springer Nature. (b) Fabrication and SERS evaluation of ion-irradiated WO3 thin films. Reproduced with permission from ref. 31. Copyright 2017, American Chemical Society. (c) Schematic illustration of the PIERS technique and SERS performance of semiconductors before and after UV irradiation. Reproduced with permission from ref. 32. Copyright 2019, John Wiley and Sons. (d) AFM topographical image and SERS evaluation of the electrically tuned WO3 substrate. Reproduced with permission from ref. 36. Copyright 2019, American Chemical Society.
