Light emission from a poly-silicon device with carrier injection engineering

Development work was conducted on N+PN+PN+ Poly silicon light-emitting devices which are compatible with silicon-based integrated circuit technology. We discuss the emission characteristics of visible light by a monolithically integrated Poly-Si diode under reverse bias. With the structure of modified PN junctions, the carriers injection occurs through silicon slabs of only a few nanometer thick. The dominant role of non-radiative recombination at the N+ and P+ contacts is diminished by confining the injected carriers around the PN junction's interface in which avalanche takes place. The current-dependent optical radiation presents a broad spectrum in the 400- to 900-nm range. Although the emission efficiency is low due to silicon's indirect bandgap, it is advantageous to utilize these devices in all-silicon optoelectronic integrated circuits (OIC's).