ABSTRACT
The hope that silicon could be used as a light-emitting material in the visible arose in 1990 when efficient visible light from porous silicon (PS) was demonstrated at room temperature. The basic period of the superlattice was formed by a monolayer of adsorbed oxygen and a thin molecular beam epitaxy-deposited single crystal Silicon layer. The luminescence was attributed to quantum confinement as well as Si/O binding regions. Electrons from the substrate are injected into Silicon nanocrystals under cathodic bias and reduction of persulphate ions occurs. Oxidation occurs at the internal surface, where holes supplied by the substrate are injected. Layer capping and encapsulation techniques have been proposed in order to prevent the contamination of PS by all sorts of molecules present in ambient atmosphere.
