Enhanced surface passivation of epitaxially grown emitters for high-efficiency ultrathin crystalline Si solar cells

Abstract

In this work, we demonstrated an enhanced surface passivation of epitaxially grown boron-doped emitters by replacing thermal SiO 2 as a passivation layer of p+-emitter employed in a 16.8% efficient 18-μm Si solar cell on stainless steel with plasma assisted atomic layer deposition (ALD) Al 2 O 3 /PECVD SiN x stack. For the Al 2 O 3 /SiN x stacks on epitaxial p+-emitter after post-deposition anneal, the emitter saturation current density (J 0e ) values were decreased to 19.5 fA/cm2 with the corresponding iV oc of 688 mV By using advanced surface passivation scheme, further improvement in the V oc of a present 16.8% efficient ultrathin Si solar cell on steel can be expected.