A Novel Atomic Layer Deposited Al2o3 Film With Diluted Nh4oh For High-Efficient C-Si Solar Cell

In this paper, Al2O3 film deposited by thermal atomic layer deposition (ALD) with diluted NH4OH instead of H2O was suggested for passivation layer and anti-reflection (AR) coating of the p-type crystalline Si (c-Si) solar cell application. It was confirmed that the deposition rate and refractive index of Al2O3 film was proportional to the NH4OH concentration. Al2O3 film deposited with 5 % NH4OH has the greatest negative fixed oxide charge density (Q(f)), which can be explained by aluminum vacancies (V-Al) or oxygen interstitials (O-i) under O-rich condition. Al2O3 film deposited with NH4OH 5 % condition also shows lower interface trap density (D-it) distribution than those of other conditions. At NH4OH 5 % condition, moreover, Al2O3 film shows the highest excess carrier lifetime (tau(PCD)) and the lowest surface recombination velocity (S-eff), which are linked with its passivation properties. The proposed Al2O3 film deposited with diluted NH4OH is very promising for passivation layer and AR coating of the p-type c-Si solar cell.