This paper presents the results of the preparation and electrical characterization of Ru–Si–O thin-film nanocomposites deposited by magnetron sputtering (pDC) with varying oxygen content ranging from 0% to 50%. Measurements were conducted over a wide frequency range of 50 Hz–5 MHz and temperatures of 20–373 K. Conductivity analysis revealed that DC conduction occurs at low frequencies (≤103 Hz), while an increase in conductivity associated with electron tunneling mechanisms is observed at higher frequencies. The determined charge transport activation energies range from 3 × 10−4 eV for the oxygen-free sample to 6 × 10−2 eV for the high-oxygen samples, indicating a significant effect of composition on the conduction mechanisms. In samples containing 30% and 50% oxygen, two characteristic frequency ranges for the activation of transport processes were observed (e.g., ~102–103 Hz and 104–106 Hz), suggesting the coexistence of multiple tunneling mechanisms. Phase angle analysis revealed a transition from values near –90° at 151 K to values near 0° at 333 K, characteristic of parallel RC systems. The minimum dielectric loss tangent occurs in the range of 103–105 Hz, corresponding to Maxwell–Wagner relaxation. The dispersion coefficient α reaches maximums in two frequency ranges, decreasing with increasing oxygen content. EDS analysis showed a decrease in Ru content from ~24.9 at.% (0% O2) to ~0.7 at.% (50% O2) and an increase in oxygen content to ~78 at.% at 10% O2. The results confirm the transition from metallic conduction to tunneling and hopping mechanisms with increasing oxidation state of the structure.
Wilczyńska et al. (Sun,) studied this question.