论文部分内容阅读
Despite the optical advantage of near-zero reflection, the silicon nanowire arrays (SiNWs) based solar cells cannot yet achieve satisfactory high efficiency due to the serious surface recombination arising from the greatly enlarged surface area.The trade-off between reflection and recombination fundamentally prevents the conventional SiNWs structure from having both minimal optical and electrical losses.Here we report the simultaneous realization of the best optical anti-reflection (the solar averaged reflectance of 1.38%) and electrical passivation (the surface recombination velocity of 44.72 cm/s) by effectively combining the Si nano/micro-structures (N/M-Strus) with ALD-Al2O3-passivation.The composite structures are pre-pared on the pyramid-textured Si wafers with large-scale 125 × 125 mm2 by the two-step metal-assisted chemical etch-ing method and the thermal atomic-layer-deposition (ALD)-Al2O3 treatment.While the excellent optical an-ti-reflection is observed due to the complementary contribution of Si N/M-Strus at short wavelength and ALD-Al2O3 at long wavelength, the low recombination has also been realized since the field effect passivation is enhanced for the longer-and-thinner SiNWs through the more effective suppression of the minority carrier movement and the reduction of the pure-pyramid-textured surface recombination.We have further numerically modeled the Al2O3-passivated Si N/M-Strus based solar cell and obtain the high conversion efficiency of 21.04%.The present work opens a new way to realize high efficiency SiNWs based solar cells.