LIGHT-INDUCED ELECTROLUMINESCENCE OF POROUS SILICON LAYERS ON P-SI INPERSULFATE SOLUTION

Electroluminescence has been observed using the photostimulated reduct ion of persulfate ions at porous silicon layers grown on p(-)-Si subst rates. Electrons were generated in the substrate by illumination from the ohmic contact side. The detection of visible electroluminescence s hows that photogenerated electrons accumulate in the porous layer when the p(-) substrate is reverse biased. Voltage tuning of the electrolu minescence spectrum was observed, but the tuning saturated when the re duction of persulfate became light limited. The tuning is attributed t o the switching on of electroluminescence as electrons progressively p opulated particles of decreasing size, followed by switching off by Au ger quenching when a second electron is captured before radiative deca y occurs. (C) 1996 American Institute of Physics.