DC and AC Hopping transport in metal/amorphous carbon nitride/metal devices

Hopping electrical transport has been investigated in amorphous carbon nitride in both DC and AC modes, as a function of temperature T, electric field F and frequency. The strong field enhancement of the current for F > 5 × 104 V cm−1, causing a departure from the Mott law at low field, i.e. the linear dependence of ln(σOHMIC) vs (T0/T)1/4, is also observed in the AC conductance data. Both conductance and equivalent parallel capacitance are discussed in the framework of a universal model of AC transport with spatially randomly distributed energy barriers. The inverse characteristic time 1/τ, which also follows Mott’s law, is compatible with the filling rate ΓF(EDL) of empty states at the transport energy, which governs the DC conductivity.