Optical properties of silicon network polymers

Summary form only given. Recently, /spl sigma/-conjugated Si polymers have attracted considerable attention, because they have a potential as future optoelectranic devices. Since the local Si structures can be controlled in Si polymers, they are model materials for the understanding of electronic properties of various Si based-materials. In this work, we have studied optical properties of Si polymers with network backbone structures. Three types of planar Si polymers [ladder and network structures, and planar siloxene] were synthesized. These network polymers serve as a conceptual bridge between one-dimensional polymers and fully coordinated amorphous silicon. In the ladder and network Si polymers, broad photoluminescence (PL) spectra are observed at the visible spectral region. The PL intensity from oxidized network polymers (planar siloxene) is very large compared with that from other network Si polymers. Oxygen atoms modify the electronic structures of quasi two dimensional Si structures. Moreover, the exciton absorption and PL bands in the three Si network polymers are broad compared with those of one-dimensional chain structures. The optical properties of Si polymers are sensitive to the dimensionality and disorder of the silicon backbone structure.