An admittance spectroscopy study of grain and grain boundary of diamond

AC electrical response of polycrystalline diamond films, prepared by hot-filament assisted chemical vapor deposition technique, was studied8 by admittance spectroscopy. Temperature dependent admittance evidenced two main exponential regimes associated with distributions of traps9 within diamond grains and at grain boundaries, respectively. Activation energies of the low-frequency conductance and of the characteristic10 relaxation frequency from Jonscher equation also evidence two trap levels associated to grain and grain boundary. This picture is supported by11 capacitive contributions obtained from imaginary part of electric modulus spectra, furthermore suggesting the presence of charge carriers tunneling12 at the Fermi level. Results are discussed in terms of a schematic band energy diagram