High-efficiency c-Si solar cells passivated with ALD and PECVD aluminum oxide

Ultrathin (7 nm) atomic layer deposited Al2O3 layers and high-deposition-rate plasma-enhanced chemical vapor deposited AlOx layers have been applied and characterized as rear-surface passivation for high-efficiency silicon solar cells. The excellent efficiency values (up to 21.3%-21.5%) demonstrate that both aluminum oxide deposition processes have a very high potential comparable to the reference cells with SiO2 passivation. The high voltages (similar to 680 mV), the excellent long-wavelength quantum efficiency, and the high short-circuit currents of these cells (similar to 40 mA/cm(2)) are a proof for the low rear-surface recombination velocity and excellent internal rear-surface reflection.