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 Seff =3±1 cm/s at τn= 1015 cm-3 in the as-deposited state. Illumination induces an increase to Seff =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 °C for 5 min.