This book, first published in 2001, provides an international forum to exchange research results on topics ranging from silicon thin-film physics and chemistry, to novel device design and engineering. It covers all aspects of hydrogenated amorphous silicon (a-Si:H) science and technology, and is the fourth consecutive volume in the series to cover heterogeneous silicon film materials, including the nanocrystalline, microcrystalline, and polycrystalline films. A special 'Millennium Session' celebrating the most important achievements of the last three decades in the field of amorphous and microcrystalline silicon thins films, is featured. Topics include: amorphous film growth and properties; nanocrystalline/microcrystalline film growth and properties; ordering, ordering transitions and photocrystalline films: polycrystalline films, epitaxial growth and properties; catalytic/hot-wire CVD - amorphous to polycrystalline films; implantation, annealing and crystallization; structure and hydrogen; band, band tails and defect states; metastability and equilibration; thin-film transistors, displays and imagers; thin-film solar cells and solar-cell structures; amorphous silicon detectors and other devices; and heterogeneous silicon transport and device applications.