Critical behavior of the dielectric properties near the metal-non-metal transition in Cr/p + a-Si:H/V thin film devices

Abstract

The ac conductivity data for Cr/p + hydrogenated amorphous silicon/V thin film devices, measured over a frequency range of 1 Hz to 30 MHz and a temperature range 13–300 K, has been modelled using multi-component RC and RL equivalent circuits below and above the metal-non-metal (MNM) transition region respectively. The capacitance (dielectric constant) anomaly near the metal-non-metal transition is explained in terms of a percolation-like critical behaviour of the dielectric constant ε eff, which diverges at the threshold of the volume fraction of the metallic particles, p c.