Structural properties depicted by optical measurements in hydrogenated polymorphous silicon

Hydrogenated polymorphous silicon (pm-Si:H) is a new material obtained by p lasma-enhanced chemical vapour deposition by running the plasma close to po wder formation. Preliminary studies have revealed the presence of silicon n anocrystallites embedded in an amorphous matrix but only in a limited range of deposition conditions. In this work we have investigated the structural properties of such films by means of spectroscopic optical measurements. T he analysis of transmission spectra in the transparent region has shown tha t pm-Si:H films have indeed a more ordered structure than state-of-the-art hydrogenated amorphous silicon (a-Si:H) films. This has been observed in th e whole range of deposition conditions leading to pm-Si:H films. On a final point the implication of structural properties on the excellent optoelectr onic properties previously reported in pm-Si:H films is discussed.