In addition to traditional themes of synthesis, structure and optoelectronic properties of nano- and microcrystalline semiconductors, this book, first published in 1999, reports on properties leading to new optical and biological applications. Individual nanocrystals, as well as nanocrystalline and microcrystalline semiconductors and thin films, represent an interesting class of materials whose properties differ from those of their single-crystal and amorphous counterparts. For example, the electrical, optical and chemical properties may be dominated by surface- and grain-boundary phenomena, and quantization can alter the electronic states. Such effects lead to unique properties that are sensitively dependent on the crystallite size and may be exploited in novel optoelectronic, sensor and biomedical devices. Researchers come together here to share recent advances in the field. Topics include: light emission from nanocrystalline silicon; biological applications and surface chemistry of nanocrystalline semiconductors including synthesis and spectroscopy; synthesis and properties of microcrystalline and nanocrystalline semiconductors; oxide and chalcogenide semiconductors and microcrystalline and polycrystalline semiconductors.