Highly efficient surface enhanced Raman scattering activation of vertically etched hydrogen-terminated semiconducting mesoporous silicon

Surface enhanced Raman scattering (SERS) of the various semiconductors remains a hot research spot. We investigate the SERS activation of the vertically etched hydrogen-terminated semiconducting mesoporous Si films. The results indicate that the thin mesoporous Si layer with small pore dimensions has very low limit of detection (3.2 x 10-9 M) of the adsorbed rhodamine 6 G molecules owing to the suppressed diffusion of the molecules in the pores such that they stay in the shallow layer. The vertically etched mesoporous Si substrate is much superior to the planar Si substrate regarding the SERS activation. The observed SERS activation is partially ascribed to the efficient excitation of the oscillating electric dipoles at the organic molecule-semiconductor interface.