Light induced defects in sputtered amorphous silicon thin films

We have investigated the influence of light soaking on the electrical and optical properties of sputtered amorphous silicon thin films. The obtained results have shown that sputtered a-Si:H films, as well as glow discharged material are sensitive to prolonged light exposure. The most important induced states appear during the first 2 h of exposure. From the dark conductivity variation, we inferred that light induced defects are relatively low in hydrogen-rich films. We suggest that the mechanism of defect creation is performed through SiSi weak bonds breaking and that is stabilized by hydrogen involvement.