LIGHT-EMITTING POROUS SILICON FROM CAST METALLURGICAL-GRADE SILICON

Strong visible light emissions from porous silicon (PS) prepared from cast metallurgical-grade silicon (MG-Si) are reported for the first ti me. The Si substrates used for the preparation of the PS films were ob tained by directional solidification casting of MG-Si, followed by waf er sawing and lapping. A chemical etching method was used instead of t he conventional electrochemical method of producing PS. The photolumin escence spectra are characterized by a full width at half maximum of 3 40 to 370 meV, a 2.0 eV peak energy, and a strong peak intensity.