ATOMIC-LAYER-DEPOSITED ALUMINUM OXIDE FOR THE SURFACE PASSIVATION OF HIGH-EFFICIENCY SILICON SOLAR CELLS

摘要

We present independently confirmed efficiencies above 20% for PERC-type solar cells with the point-contacted rear being either passivated by atomic-layer-deposited Al_2O_3 or by stacks consisting of an ultrathin Al_2O_3 film and a thicker PECVD-SiO_x layer. Internal quantum efficiency measurements reveal that the effective rear surface recombination velocities of the single-layer Al_2O_3-passivated cells are comparable to those measured on reference cells passivated by an aluminum-annealed thermal SiO_2, while those of the Al_2O_3/SiO_x-passivated cells are even lower. Very low effective rear surface re-combination velocities of only 70 cm/s are reported for the Al_2O_3/SiO_x stacks, including metalized areas on the cell rear.