Role of surface in light induced degradation of porous silicon

Exposure of porous silicon (PS) to moisture is found to increase its photoluminescence (PL) intensity, whereas it decreases drastically upon light soaking. On the other hand, coating by a thin layer of polystyrene protects PS against light induced degradation without changing PL significantly. Further, polystyrene coating protects the PS from humidity also. FTIR shows appearance of new bonding configurations at the PS/polymer interface, whcih may account for the improved stability. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)