ELECTRICALLY-INDUCED SELECTIVE QUENCHING OF POROUS SILICON PHOTOLUMINESCENCE

Visible photoluminescence (PL) of porous silicon is found to be completely quenched by the application of a cathodic polarization. Cathodically biased lightly doped n-type porous layers in contact with an aqueous solution exhibit reversible, complete and energy-selective quenching for a polarization variation of only about 500 mV. A spectral blueshift along with a narrowing of the line width accompanies the observed strong PL quenching. It results from a selective quenching starting by the low luminescence energy and reaching progressively the high luminescence energy as the cathodic polarization is increased.