CVD synthesis of carbon-based metallic photonic crystals

Three-dimensionally periodic nanostructures on the scale of hundreds of nan ometers, known as photonic crystals, are attracting increasing interest bec ause of a number of exciting predicted properties. In particular interestin g behavior should be obtainable for carbon-based structures having a dimens ional scale larger than fullerenes and nanotubes, but smaller than graphiti c microfibers. We show here how templating of porous opals by chemical vapo r deposition (CVD) allows us to obtain novel types of graphitic nanostructu res. We describe the synthesis of new cubic forms of carbon having extended covalent connectivity in three dimensions, which provide high electrical c onductivity and unit cell dimensions comparable to optical wavelengths. Suc h materials are metallic photonic crystals that show intense Bragg diffract ion. (C) 1999 Acta Metallurgica Inc.