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 $13cm∕s$ on low resistivity $n$- and $p$-type $c-Si$⁠, respectively. These results obtained for $∼30nm$ 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 $7nm$ thin $Al2O3$ film still yields an effective surface recombination velocity of $5cm∕s$ on $n$-type silicon.