LIGHT-INDUCED METASTABLE EFFECTS ON THE ELECTRICAL CONDUCTANCE IN POROUS SILICON

Abstract

Persistent photocurrent (PPC), i.e., a photocurrent which has a very long decay time after a brief light exposure has been observed in porous silicon at low (less than or equal to 300 K) temperatures. The porous silicon in our experiment has been characterized by the presence of an amorphous phase clarified by Raman spectra. This PPC is shown to arise if charge (electron) trapping into defects, which are believed to exist in the amorphous phase and/or at large surface of porous silicon columns, is possible.