Silicon nanowire arrays（SiNWAs） are fabricated on polished pyramids of textured Si using an aqueous chemical etching method.The silicon nanowires themselves or hybrid structures of nanowires and pyramids both show strong anti-reflectance abilities in the wavelength region of 300-1000 nm,and reflectances of 2.52%and less than 8%are achieved,respectively.A 12.45%SiNWAs-textured solar cell（SC） with a short circuit current of 34.82 mA/cm^2 and open circuit voltage（K_（oc）） of 594 mV was fabricated on 125×125 mm^2 Si using a conventional process including metal grid printing.It is revealed that passivation is essential for hybrid structure textured SCs,and K_（oc） can be enlarged by 28.6%from 420 V to 560 mV after the passivation layer is deposited.The loss mechanism of SiNWA SC was investigated in detail by systematic comparison of the basic parameters and external quantum efficiency（EQE） of samples with different fabrication processes.It is proved that surface passivation and fabrication of a metal grid are critical for high efficiency SiNWA SC,and the performance of SiNWA SC could be improved when fabricated on a substrate with an initial PN junction.
In the case of N-type solar cells,the anti-reflection property,as one of the important factors to further improve the energy-conversion efficiency,has been optimized using a stacked Al_2O_3/SiN_x layer.The effect of SiN_x layer thickness on the surface reflection property was systematically studied in terms of both experimental and theoretical measurement.In the stacked Al_2O_3/SiN_x layers,results demonstrated that the surface reflection property can be effectively optimized by adding a SiN_x layer,leading to the improvement in the final photovoltaic characteristic of the N-type solar cells.
