For the perfectly ordered graphite, the first-order Raman spectrum recorded in the near-infrared and visible light regimes shows only one peak around 1580cm-1, whereas disordered amorphous carbon generally exhibits two peaks: the so-called G-band at ~1580cm-1and the so-called D-band (disorder induced (D)) at ~1350cm-1, which is associated with the double-resonance Raman mechanism [15].