Figure 4

Infrared photoluminescence and Raman spectra: (a) the PL and Raman spectra of double side polished c-Si substrate (black curve) and a sample of SiNWs ( L  = 2.6 μm) with and without Ag nanoparticles (blue and red curves, respectively), and the inset shows the Raman peak after subtraction of the PL background; (b) Raman spectra the samples of SiNWs with two different thicknesses, and the inset shows dependence of the Raman intensity on the length of SiNWs (dashed red curve corresponds to a fit by the logarithmic function).