We have measured I-V and C-V characteristics, the temperature dependence of dark currents, and thermally stimulated depolarisation currents on fresh and stored samples of photoluminescent porous silicon. By storage in ambient, the low rectifyingI-V curves become strong rectifying, and C-V curves become MIS-like. I-T characteristics for fresh samples have only one activation energy, in the 0.49-0.55 eV range. After storage, a slightly modified value, of about 0.50-0.60 eV is observed at lowtemperatures only. At about 280 K, the activation energy suddenly changes to 1.20-1.80 eV. Also, both the number and the positions of maxima in thermally stimulated depolarisation currents change by storage. The annealing at about 50℃ induces smallreversible changes in f-T characteristics and strong irreversible ones in thermally stimulated depolarisation currents, both for fresh and stored samples. A simplified quantum confinement model is proposed to explain the main aspects of the electricalbehaviour of porous silicon films. The surface and/or interface contributions are observed especially in thermally stimulated depolarisation currents. The changes induced by storage are attributed to the oxidation process of the internal surface of porous silicon films.
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