Figure 2.

Raman spectra of a representative selection of composite samples. Raman spectra of silica aerogel (black, top) and aerogels containing (top to bottom) LH, LO and SO particles (blue, red and green, respectively). The vertical dashed lines indicate the Raman shifts of (left) the bulk silicon and (right) the silica D₂ defect modes. For one of the aerogels containing LO particles, a representative fit to the data (discussed in the text) and its three components are shown (black and grey solid lines).