Effect of Al2O3/ZnO Nanolaminate by Atomic Layer Deposition (ALD) on p-Si Photocathode for Photoelectrochemical Hydrogen Evolution

Abstract

Al2O3/ZnO (AZO) nanolaminate layer was deposited by atomic layer deposition (ALD) on p-type Si planar photocathode for photoelectrochemical hydrogen evolution reaction. ALD is the excellent method to deposit nanofilms with uniform morphology. AZO nanolaminate layer was expected to protect the p-Si photocathode from oxidation in an ambient condition, and to offer the surface passivation to prevent surface recombination. The % of Al2O3 in AZO was controlled in AZO layer, 100, 80, 50, 20%, and 100% ZnO, on the p-Si photocathode. The total thickness of AZO was fixed at similar to 2 nm by the number of ALD cycles. From the current density versus potential (J-V) curve, 100% Al2O3 showed the lowest overpotential.