ELECTRICAL-PROPERTIES OF LUMINESCENT POROUS SILICON

The relation between the visible luminescence of porous silicon (PS) and its electrical properties has been investigated with an emphasis on carrier transport, photoconductivity, and the effects of an external electric field on the photoluminescence (PL). The PS layers are formed by anodization of p- or n-type Si wafers in an HF solution in the dark or under illumination. At first, the correlation of the electrical conduction mode with the PL efficiency is shown using a self-supporting PS film as a sample. Next, the photoconduction effects of PS for visible light are characterized for the experimental cells of the form (semitransparent thin Au film/PS/Si substrate/Al contact). Finally, the reversible electrical PL quenching is demonstrated. These results support the hypothesis that the visible luminescence of PS is based on surface-sensitive quantum confinement effects in Si nanocrystallites.