Novel applications of porous silicon

Porous silicon is best known for its applications in the oxide isolation of silicon integrated circuits. However, porous silicon is a very versatile material and its unique properties are being researched for a surprising range of applications. These include use as a substrate for epitaxial growth, for the production of ``smart´´ dielectrics, for the location of defects in other silicon-on-insulator materials, for the producion of sensors, for conversion to metal and for the emission of visible light. These and others are described.