Ultra Thin Al2O3  passivation for hetero-junction Si solar cell
Sangpyeong Kim, Pradeep Balaji, Andre Augusto, Stuart Bowden, Christiana Honsberg
Arizona State University, Tempe, AZ, United States

We study the potential of using  Al2O3 as a more transparent  passivation layer for silicon heterojunction solar cell. We have optimized the post-annealing process to activate the Al2O3 layer. With 10nm Al2O3 layer the effective  minority-carrier lifetimes surpassed the 3 ms and implied open-circuit voltages were over 700 mV. The thick Al2O3 layers prevents the carrier transport to the metal contacts.  The first results on very thin layers of Al2O3  show severe degradation both in lifetime and voltage.