Raman spectroscopy of porous silicon substrates

We have investigated the effect of the etching time on the Raman spectra of porous silicon prepared by anodic etching. Electrochemical destruction of the substrate increasing with the etching time and the correlation between the microstructure of the silicon wafer and the shape and position of their Raman spectra have been observed. Raman analysis has shown that the intensity of the Raman dominant silicon band decreases and the bandwidth is shifted to lower frequencies, depending on the morphology of the sample. Therefore we believe that the electrochemical destruction of the surface of Si substrates leads to surface amorphization.