Solar Energy Materials and Solar Cells, Vol.93, No.2, 215-221, 2009
Fabrication of beta-FeSi2/Si composite films for photovoltaic applications by using scanning annealing
For use as superior photovoltaic materials, thin beta-iron silicid (beta-FeSi2) nanoparticles/Si composite films were fabricated by using rf-magnetron sputtering and post scanning annealing. After the scanning annealing at a preheating temperature of 800 degrees C, transmission electron microscopy (TEM) observation was then used to confirm 10-50-nm nanoparticles in FeSi2 = 8.4 at% composite films. Amorphous and single-phase FeSi2 films were also crystallized by the scanning annealing to determine the type of crystal phase of the nanoparticles. Lower preheating temperature (<800 degrees C) yielded beta-FeSi2 films, whereas higher preheating temperature (>900 degrees C) yielded alpha-FeSi2 films. TEM observation and X-ray diffraction (XRD) analysis confirmed the successful fabrication of beta-FeSi2 nanoparticles/Si composite films. In conclusion, the photoabsorbance of thin Si films at wavelengths between 500 and 800 nm was significantly enhanced by fabrication with beta-FeSi2. The photoabsorption spectra could be controlled by changing the diameter of the nanoparticles. The nanoparticle diameter depended on the deposition conditions and the preheating temperature. (C) 2008 Published by Elsevier B.V.