Recombination at a-Si:H/c-Si heterointerfaces and in a-Si:H/c-Si heterojunction solar cells

The consequences of post-deposition thermal annealing on the recombination velocity at a-Si:H/c-Si heterocontacts and on the performance of a-Si:H/c-Si heterojunction solar cells are investigated. We use a substrate temperature of 110 /spl infin/C for the deposition of the a-Si:H hetero-emitters and a post-deposition anneal for 10 min at 200 /spl infin/C to obtain optimum results in terms of interface recombination velocity, interface defect density, and solar cell performance. Our best solar cell using a p-type FZ base in combination with a-Si:H heterojunction and a metallic Pd/Al back contact has a confirmed efficiency of 15.4% and an open circuit voltage V/sub OC/=658 mV. Solar cells that use a i/p/sup +/ a-Si:H double layer as a back contact obtain a maximum V/sub OC/ of 685 mV but suffer yet from a relatively low fill factor.