Staebler-Wronski-like formation of defects at the amorphous-silicon-crystalline silicon interface during illumination

The effective surface recombination velocity of amorphous-silicon-coated crystalline silicon wafers is measured after illumination for various durations to investigate the stability of the surface passivation. We develop a defect model to determine the densities of dangling bond states at the a-Si:H/c-Si interface from fitting the experimental lifetime data. The surface recombination velocity of both p-type and n-type substrates is S-eff=3 +/- 1 cm/s at tau n=10(15) cm(-3) in the as-deposited state. Illumination induces an increase to S-eff=16 +/- 5 cm/s due to an increase in the dangling bond density by one order of magnitude. This increase is reversible by annealing at 300 degrees C for 5 min. (C) 2008 American Institute of Physics.