Within silicon, silver is an impurity with fast diffusivity and deep levels
. It forms effective recombination centres in silicon acting as either acce
ptor or donor levels. That has been confirmed by a depth-profile analysis w
ith the SIMS. The silver atoms do exist near the barrier region of a solar
cell with Ti/Pd/Ag electrodes heated at 245 degreesC for 308 h. The open-ci
rcuit voltage at low injection decreases as recombination actions increase
in the barrier region. According to these phenomena, an estimation for the
lifetime of solar cells is given by using acceleration stress tests. (C) 20
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