Strong enhancement and long-time stabilization of porous silicon photoluminescence by laser irradiation

A remarkable enhancement in photoluminescence (PL) intensity of porous silicon (PS) by a factor of over 250 was observed by laser irradiation. The long-time stabilization of the PL was confirmed by PL measurements at intervals of 10 days in aging time (after 10, 20 and 30 days of aging). The composition of the PS surface was monitored by transmission FT-IR spectroscopy and it was found that the PS surface oxidation significantly progresses by the laser heating effect. The experimental results suggest a possibility that laser irradiation provides a relatively easy way to achieve the efficient and stable PS luminescence.