Figure 2.

The background subtracted Raman spectra of NCD film grown for six hours on single crystal diamond and for two hours on silicon substrate. Peaks at 1150 cm⁻¹, 1190 cm⁻¹, 1350 cm⁻¹, 1480 cm⁻¹ and 1550 cm⁻¹ are attributed to sp² bonded carbon and transpolyacetylene, and are characteristic of NCD films. A very weak 1332 cm⁻¹ Raman peak corresponding to sp³ bonded carbon is also observed for NCD films in both cases.