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wileyonlinelibrary.comand short-wavelength spectral response is not good enough, mainly due to the large recombination loss of back surface fi eld (BSF) [ 2 ] and the high residual refl ectance at the front surface, [ 3 ] respectively. To achieve the excellent broadband spectral response of the Si based solar cells, it is necessary to further improve the optical and electrical properties of the rear surface as well as the front surface. By introducing passivation dielectric thin fi lms at the rear surface, Green group [ 4 ] has successfully fabricated a 22.8% effi cient passivated emitter and rear cell (PERC) with an area of 4 cm 2 , manifesting superior long-wavelength spectral response due to the low recombination velocity and high long-wavelength refl ectivity at the rear surface. [ 5 ] This longwavelength superiority has been recently employed in the photovoltaic industry for the mass production of 20.0% effi cient PERCs on commercial large-area (156 × 156 mm 2 ) Si wafers. [ 6,7 ] On the other hand, Si nanostructure array provides a promising approach to enhancing the energy harvesting in the shortwavelength range, for the near zero and small-angle-dependent refl ectivity in the short-wavelength region. [8][9][10][11][12][13][14][15] By employing the well short-wavelength antirefl ection of the Si nanostructure array, many authors have made relative progresses in the cell performances of the Si nanostructures based solar cells. [16][17][18][19][20][21] But η 's of these Si nanostructures based solar cells are still not satisfi ed when comparing with those of the traditional solar cells, which is mainly attributed to the large surface recombination loss from the Si nanostructures. Surface passivation such as thermal SiO 2 , [ 4,11,22 ] SiN x :H by plasma enhanced chemical vapor deposition (PECVD), [ 23,24 ] and Al 2 O 3 by atomic layer deposition (ALD) [25][26][27] can effectively suppress the surface recombination by saturating the dangling bonds or forming the fi xed charges at and near the surface. Particularly, the stack SiO 2 /SiN x layers provide an excellent passivation for the Si nanostructures, [28][29][30] which benefi ts from the well surface passivation of the inner SiO 2 as well as the bulk passivation of the outer SiN x :H. The simultaneous surface and bulk passivation guarantee the well electrical performance of the Si nanostructures based solar cells.As a result, the passivated front Si nanostructures together with the passivated rear surface are able to provide the complementary spectral responses in both the short-wavelength and long-wavelength region, implying an effective way to achieve the excellent broadband spectral response of Si based solar cells. In this paper, 20.0% Effi ciency Si Nano/Microstructures Based SolarSpectral response of solar cells determines the output performance of the devices. In this work, a 20.0% effi cient silicon (Si) nano/microstructures (N/M-Strus) based solar cell with a standard solar wafer size of 156 × 156 mm 2 (pseudo-square) has been successfully fabrica...

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