Temperature-dependent conduction of W-containing composite diamond films

We report on the synthesis and electrical characterizations of composite W-containing diamond films. These layers have been produced by a hybrid chemical-vapor-deposition/powder flowing technique that allows control of the dispersion of the foreign W phase inside a diamond matrix. The electrical behavior of such material in the 25–500 K temperature range is found characterized by a nonlinear response, typical of metal/insulator composite materials, with conductivity reaching the maximum value of 95 Ω−1 cm−1 at 148 K. Structural and morphological investigations performed by reflection high-energy electron diffraction, scanning electron microscopy, and dispersive x-ray spectrometry indicate that the presence of a percolating network of metallic grains did not perturb the quality of the diamond lattice. © 2001 American Institute of Physics. © 2001 American Institute of Physics