Abstract

The photoluminescence (PL) in crystalline silicon (c-Si) has been investigated during the last decades. Interest has focused on the visible PL that is observed in Si nanoclusters and in porous Si (PSi), the infrared PL in silicon-germanium superlattices, and the subgap PL due to impurities in c-Si [1]. Whereas strong room-temperature PL has been demonstrated in the visible with porous silicon, band edge PL in bulk Si is inefficient and usually observed only at low temperatures. The electroluminescence (EL) is as inefficient as the PL, and, in addition, the EL is quenched by an electric field E ≥ 10⁴V/cm due to field-induced dissociation of the exciton [2]. A result of the indirect bandgap of Si, bandgap luminescence is extremely weakly reabsorbed by Si. It follows that the light generated, propagated, and detected at the Si bandgap would not disturb the Si microelectronic circuitry with which it shares a chip, a situation that is very desirable for systems applications.

© 1997 Optical Society of America