Metal-containing diamond-like carbon-silicon nanocomposite films as temperature sensors

Metal-carbon nanocomposites are characterized by a number of unique properties, perspective for the various-type applications. The presented experimental data on the conductivity of amorphous tungsten- and niobium-containing carbon-silicon nanocomposite films show the possibility of the design of advanced wide-range temperature sensors, which are expected to possess the chemical stability, biocompatibility, mechanical, and other properties typical for this class of materials. The films were deposited onto polycrystalline substrates using combination of PECVD(Plasma Enhanced Chemical Vapor Deposition) of siloxane vapors and magnetron co-sputtering of metal target. The conductivity σ of the films, measured using standard 4-probe technique in the temperature range 80-400K, is characterized by the gradual decrease with temperature. The experimental σ(T) dependences are well fitted by the universal power expression, σ(T)= σ₀+aTⁿ, where σ₀, a, and n are the fitting parameters dependent on the value of metal concentration. The conductivity mechanisms in the investigated amorphous metalcontaining carbon-silicon nanocomposite films are discussed in the framework of the model of inelastic tunneling in amorphous insulators in the presence of the structural transformation in carbon-silicon matrix.