Dual Function of Antireflectance and Surface Passivation of Atomic-Layer-Deposited $\hbox{Al}_{2}\hbox{O}_{3}$ Films

Surface antireflectance and passivation properties of the Al
₂
O
₃
films deposited on Czochralski Si wafers by atomic layer deposition (ALD) are investigated. Textured Si with 100-nm Al
₂
O
₃
shows a very low average reflectance of ~2.8%. Both p- and n-type Si wafers are well passivated by Al
₂
O
₃
films. The maximal minority carrier lifetimes are improved from ~10 μs before Al
₂
O
₃
passivation to above 3 ms for both p- and n-type Si after Al
₂
O
₃
film deposition and annealing at an appropriate temperature. Hence, an ALD-deposited Al
₂
O
₃
film shows the dual function of antireflectance and surface passivation for solar cell applications.