Nanosurface Passivation with Indium Tin Oxide and Aluminum Oxide Double Layer on Nanotextured Silicon Solar Cells

We investigated the characteristics of the double thin film layers of indium tin oxide and Al2O3 as the anti-reflection coating layer on nanotextured Si solar cells in order to enhance the carrier collection by the indium tin oxide thin film as a transparent metamaterial. The nanotextured surface was formed on the microtextured surface by a metal-assisted chemical etching process. The double thin film layers with various thicknesses were deposited by a radio-frequency magnetron sputter, and the indium tin oxide thin films were annealed at 400 degrees C for 10 min by rapid thermal process. Regarding cell efficiency, the nanotextured solar cell with the double layer shows the efficiency of 14.94%, and the sample with Al2O3 single layer shows 12.1%. The indium tin oxide enhances the interfacial passivation effect on nanosurfaces, and the double layers also enhance light absorption with the increased quantum efficiency in the infrared spectral region.