Scrutinization of non‒saturation behaviour of reverse current‒voltage characteristics in Ni/SiO2/p-Si/Al diodes

The present work is an endeavour to investigate non‒saturation behaviour of reverse current in Ni/SiO₂/p-Si/Al over a wide low temperature range of 70–300 K at step of 10 K using well accepted models i.e., Poole-Frenkel emission, Schottky emission and Fowler‒Nordheim tunneling mechanisms. The results of the study revealed that Schottky emission has the dominance over Poole-Frenkel emission in the temperature range of 200–300 K with the trap state activation energy of 0.17 eV. In the remaining temperature range trap assisted tunnelling and involvement of other mechanisms were suggested. Further, the Fowler‒Nordheim tunneling mechanism was found to be effective above reverse bias of 0.5 V over the entire temperature range of 70–300 K. Thus, variation of barrier height with temperature was examined using Fowler‒Nordheim tunneling model and it was found to increase from 0.17 eV to 0.28 eV as temperature varied from 300 to 70 K. The increase in barrier height with decrease in temperature corroborates the decrease in reverse current with temperature.