NONDEGRADING PHOTOLUMINESCENCE IN POROUS SILICON

Porous silicon (PS) with nondegrading photoluminescence (PL) was prepa red by a novel method. For fresh samples, the PL peak intensity is 2-2 .5 times stronger than that in normal PS. Upon exposing PS to ambient air, the PL intensity increases during the first four months and then saturates. No PL degradation is observed for eight months, and the pea k position remains unchanged. The same effect can also be achieved by annealing treatments, This PL stability is attributed to the formation of stable Fe-Si bonds on the surface of PS. Exploration of the mechan ism provides strong proof of the quantum confinement model of the lumi nescence Of PS. [S0031-9007(98)06914-2].