Tuning by means of laser annealing of electronic and structural properties of nc-Si/a-Si:H

We report the effect of laser annealing on the structural and electronic properties of nc-Si/a-Si:H samples grown close to the amorphous to nanocrystalline transition. The nc-Si/a-Si:H thin films were produced by low-energy plasma-enhanced chemical vapor deposition through a gas discharge containing SiH4. The samples were subjected to different laser fluencies and were characterized for changes in their structural and electronic properties via Raman spectroscopy and photoluminescence measurements. The laser annealing effects are twofold: i) the nanocrystalline phase grows, during the laser treatment, respect to the amorphous phase; ii) the photoluminescence spectra show the suppression, after laser annealing, of the frequencies above the crystalline Si band–gap.