Dual functions of anti-reflectance and surface passivation of the atomic layer deposited Al2O3 films on crystalline silicon substrates

Surface anti-reflectance and passivation properties of the Al2O3 films deposited on crystalline Si substrates by atomic layer deposition are investigated. Textured Si with 100 nm Al2O3 shows a very low average reflectance of ~2.8 %. Both p-type and n-type Si wafers are well passivated by Al2O3 films. The maximal minority carrier lifetimes are improved from ~10 {\mu}s before Al2O3 passivation to above 3 ms for both p-type and n-type Si after Al2O3 passivation layer deposition and annealing at an appropriate temperature. Our results indicate the dual functions of anti-reflectance and surface passivation in c-Si solar cell applications.