This book comprises the contributions to the sixth conference on polycrystalline semiconductors (POLYSE). The conference covered many aspects of polycrystalline semiconductors, but was more applications-oriented than on previous occasions; thereby reflecting the rapid evolution of these technologies. POLYSE 2000 brought together research specialists from basic research, as well as from research & development engineering, all of whom are working on devices such as thin-film transistors, micro-electromechanical systems, or sensors and actuators. In particular, ten internationally recognized scientists (J. Morante, S.Périchon, M. Konagai, S. Wagner, R. Hagenbeck, D.A. Bonnell, G. Horowitz, T.Fuyuki, J. Kocka and V. Chuwere) were invited to review their work on several interesting and promising aspects of the subject: such as, micro-systems, solar cells, thin-film transistors, organic polycrystalline devices and polycrystalline ceramics.