Effect of DC bias on electrical conductivity of nanocrystalline α-CuSCN

The grain boundary space charge depletion layer in nanocrystalline alpha phase CuSCN is investigated by studying electrical properties using impedance spectroscopic analysis in frequency domain. The measurements were performed at room temperature in wide frequency range 1 Hz to 1 MHz under various DC bias applied voltages ranges from 0 V to -2.1 V. The effect of bias on grain and grain boundary contribution electrical conductivity has been investigated by equivalent circuit model using non-linear least squares (NLLS) fitting of the impedance data. Three order of magnitude variation of grain boundary conductivity was observed for varying 0 V to -2.1 V. Variations in the σac clearly elucidate the DC bias is playing crucial role on grain boundary double Schottky barriers of nanocrystalline α-CuSCN.