Transient and AC electrical conductivity of porous silicon thin films

AC impendance spectroscopy measurements as a function of the applied voltage in the range 0.5 V up to 3 V, as well as measurements of the transient current of porous silicon thin films as function of the applied voltage in the range 1V up to 9 V were performed in order to investigate the conduction mechanisms in PS. The analysis of the experimental results shows that within the range of the frequency span and time range the conductivity is attributed to ions in the early stages (up to 10(-3)s) of the applied voltage. The voltage dependence of the ionic conductivity is ohmic. The Poole-Frenkel conduction mechanism prevails following the establishment of high internal electric fields, which occur for times greater than 10(-3)s after the application of the voltage.