The effects of the time-dependent on the characteristic parameters of polypyrrole/p-type Si/Al diode

A detailed study of the effects of the time-dependent or aging on the characteristic parameters of polypyrrole/p-type Si/Al structure has been presented. The polypyrrole film has been formed on a p-type Si substrate by means of an anodization process. The polypyrrole/p-Si contact has demonstrated clearly rectifying behavior by the current–voltage curves studied at room temperature. The current–voltage (I–V) curves of the diode have been measured immediately, 7, 15, 30, 60 and 90 days after fabrication of the polypyrrole/p-Si contact. It has been seen that the characteristics parameters such as barrier height, ideality factor and series resistance of polypyrrole/p-type Si/Al structure have changed with increasing ageing time. Furthermore, the density distribution of interface states of the device was obtained from the forward bias I–V characteristics. The fact that the diode shows non-ideal I–V behavior with increasing ageing time may be ascribed to a slow replacement of the initial doping agent by oxygen and this process certainly plays a role in the aging of the diode.