Low temperature electrical conduction in thin film Cu2SnS3

Conduction mechanism was investigated from DC and AC conductivity measurements in the thin film ternary semiconductor Cu
2
SnS
3
compound. The electrical properties of this material were analyzed by impedance spectrometry (IS) in the frequency range 100 Hz – 1 MHz and in low temperature up to 77 K (−196 °C). The activation energy for the conduction process is estimated from the analysis of the temperature dependence of the DC conductivity. The AC conductivity is studied using the following equation: σ
ac
(ω) = σ
dc
+ Aω
^s
. The temperature dependence of the power law exponent s suggests that AC conduction is attributed to the correlated barrier hopping (CBH) model. Activation energy for relaxation mechanism for the grain contribution is obtained from the analysis of the temperature dependence of the corresponding relaxation time. It is found that the relaxation activation energy for the relaxation process is lower than that of the activation energy for the conduction mechanism. Finally, Nyquist representation is proposed to establish the equivalent circuit for this material in this low temperature range.