摘要
Thin films comprising nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous-carbon(UNCD/a-C:H)composite films were experimentally investigated.The prepared films were grown on Si substrates by the coaxial arc plasma deposition method.They were characterized by temperature-dependent capacitance-frequency measurements in the temperature and frequency ranges of 300-400 K and 50 kHz-2 MHz,respectively.The energy distribution of trap density of states in the films was extracted using a simple technique utilizing the measured capacitance-frequency characteristics.In the measured temperature range,the energy-distributed traps exhibited Gaussian-distributed states with peak values lie in the range:2.84×10^(16)-2.73×10^(17)eV^(-1)cm^(-3)and centered at energies of 120-233 meV below the conduction band.These states are generated due to a large amount of sp^(2)-C andπ-bond states,localized in GBs of the UNCD/a-C:H film.The attained defect parameters are accommodating to understand basic electrical properties of UNCD/a-C:H composite and can be adopted to suppress defects in the UNCD-based materials.
