Effect of light-induced defects on the short wavelength quantum efficiencies of amorphous silicon solar cell structures

Light-induced defects in intrinsic hydrogenated amorphous silicon (a-Si:H) are found to have a large effect on the short wavelength quantum efficiencies (SWQE) of a-Si:H solar cell structures. The dependence of SWQE on cell structure thickness, volume absorbed bias illumination, and externally applied voltage has been studied. The results on thick cell structures (≳0.5 μm) can be explained by a simple model which yields light-induced defects with hole capture cross sections of about 10−11 –10−12 cm2 and densities consistent with other measurements.