Recent observations of photoluminescene (PL) and electroluminescence (EL) from porous silicon (PS) have prompted many theoretical and experimental studies. Bulk crystalline Si is an indirect band gap material in which .recombination is dominated by non-radiative processes. Therefore, it cannot be used as light-emitting component in Si circuits. PS is a new material formed by anodisation ofsingle crystal Si wafers in hydrofluoric (liF) solution. Luminescence from this material is being explored

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... or technological applications all over the world. The mechanism of luminescence is still not well-understood. Several models have been proposed but still the facts about the strong light emission at room temperature are unknown. This paper presents a review of the fabrication process and studies on luminescent properties ofPS. A hybrid model based on quantum confinement of carriers in the nanometer size Si crystallites having a large number of surface states is suggested to explain the observed properties.