Ultralow surface recombination of c-Si substrates passivated by plasma-assisted atomic layer deposited Al2O3

Excellent surface passivation of c-Si has been achieved by Al2O3 films prepared by plasma-assisted atomic layer deposition, yielding effective surface recombination velocities of 2 and 13 cm/s on low resistivity n- and p-type c-Si, respectively. These results obtained for similar to 30 nm thick Al2O3 films are comparable to state-of-the-art results when employing thermal oxide as used in record-efficiency c-Si solar cells. A 7 nm thin Al2O3 film still yields an effective surface recombination velocity of 5 cm/s on n-type silicon.