In order to explain this,PC1D device modeling was performed as a function of
bulk lifetime(Fig. 7) which revealed that efficiency saturates after
250 ms bulk lifetime for our baseline cell design. Fig. 8 shows
that the implanted cells had lower Joe(70fA/cm2 vs 210fA/cm2 for
POCl3) compared to POCl3 diffused cells because of the in-situ
oxide passivation.ThelowerJoe of the implanted emitter
contributed to 6 mV higher Voc (Table1) accounting for the observed
0.3% increase in efficiency.