Nitrogen and Boron Doped Diamond Like Carbon Thin Films Synthesis by Electrodeposition from Organic Liquids and Their Characterization

摘要

Thin films of amorphous diamond like carbon (a:DLC) were deposited by using a novel technique. By electrodeposition from methanol-camphor solution thin a:DLC films were deposited on non-conductive glass substrates and also on high resistive Si substrates, by using a fine wire mesh electrode, at atmospheric pressure and temperature below 350 K. Thin films of a:DLC were doped by incorporation of nitrogen (a:N-DLC) and boron (a:B-DLC) using urea and boric acid with methanol-camphor solution respectively during the electrodeposition process. From transmittance measurements in the UV-VIS-NIR region, the optical energy band gap of about 1.0 eV for undoped a:DLC film, 2.12 eV for a:N-DLC and 2.0 eV for a:B-DLC films were determined. The spectra showed high transparency in the visible and NIR region. Fourier transform infrared spectroscopy (FTIR) measurements showed the appearance of various C-H and C-C bonding in the spectrum of undoped amorphous DLC film and confirmed C-N and C=N bond formation in a:N-DLC film. From the temperature variation of d.c. conductivity studies, the activation energies were determined and found to be 0.75 eV, 0.32 eV and 0.58 eV for undoped a:DLC films, a:N-DLC and a:B-DLC films respectively. Electrical resistivity at room temperature was reduced by the doping effect, from 109 Ω-cm for undoped films to 107 Ω-cm for nitrogen doped films and 108 Ω-cm for boron doped films.