Nanocluster carbon thin films (NC) were deposited at room temperature by cathodic arc process. These films were clustered, amorphous and disordered in nature which is verified using Raman spectroscopy. Density of defect states (DOS), which influences electronic and optical properties, were determined from the capacitancevoltage (CV) characteristic of Al/NC/c-Si metalinsulatorsemiconductor (MIS) structure near the Fermi level of undoped samples. Dielectric constant of the films was also estimated using the same technique. The DOS were found to be varying from 5.68 × 10 16 to 4.9 × 10 19 cm -3 . The dielectric constant varied between 2.76 to 11.8. © 2011 World Scientific Publishing Company.