ELECTRON-TRANSPORT AND SUPERCONDUCTIVITY IN TRANSITION METAL-CONTAINING DIAMOND-LIKE FILMS

The electron transport in W-, Mo-, and Nb-containing diamond-like film s with specific resistance of 10(-4) to 10(14) OMEGA cm is investigate d. It is shown that for most dielectric films (with low metal concentr ation) at room temperature the electric conductivity is in agreement w ith the Poole-Frenkel model and tends to be activationless following S hklovskii's mechanism at low temperatures. The transition to a low-res istance state is observed as an electric field of about 5 x 10(5) V/cm is applied. At high metal concentrations (more than 18%) evidence of superconductivity with T(c) less-than-or-equal-to 4 K is observed. At temperatures below T(c) one or two reentrant transitions to the resist ive state are revealed. The influence of the magnetic field on the sup erconducting and reentrant transitions is studied. Possible mechanisms for the reentrant transitions are also discussed.