THE QUENCHING AND RECOVERY OF PHOTOLUMINESCENCE IN POROUS SILICON

We have investigated the photoluminescence quenching of porous silicon in different atmospheres and in vacuum. We observe a much faster quen ching in vacuum than reported before, which we propose is caused by th e difference of structure in p- and n-type porous silicon, or a re-rea ction with an electrolyte vapor. We have also investigated the recover y of the photoluminescence. We observe the luminescence intensity to p artially recover under the influence of a hydrogen atmosphere, up to 0 .1 of its initial value. We propose that this is associated with the s tabilization of surface dangling bonds. When the hydrogen atmosphere w as changed to the normal atmosphere of air, the photoluminescence inte nsity started to decrease again due to oxidation. (C) 1996 American In stitute of Physics.