Antireflection and passivation property of aluminium oxide thin film on silicon nanowire by liquid phase deposition

To improve the silicon nanowires solar cell of conversation efficiency is one of the most important and challenging problems, the antireflection coatings and surface passivation technique were very important. In this investigation, aluminium oxide coatings were deposited on silicon nanowires by using liquid phase deposition. The deposition solution of aluminium sulfate and sodium bicarbonate were used for aluminium oxide deposition. The Al2O3 film can cause different surface passivation at different annealing temperatures, allowing the Al2O3/SiNWs interface to form different amounts of negatively charged AlO4 and positively charged SiOx, that the mutually suppressing action of the two oppositely charged structure. Under the optimal condition, the reflectance and effective minority carrier lifetime of liquid phase deposited aluminium oxide film were 0.97% and 31 μs, respectively. The aluminium oxide films were used herein to fabricate antireflection coating and passivation film to ensure low cost, good uniformity, favorable adhesion, mass producibility, and the formation of large-area thin film; thus, the liquid phase deposition-antireflection coating film was highly favorable for silicon-based solar cells.