Improvement of internal light-trapping for silicon based solar cells with a newly developed structure

We have systemically studied effect of n-SiO_x:H layers with relatively high oxygen content on silicon-based solar cell performance for use as a multi-functional layer. Optimization of n-SiO_x:H layers and their application to μc-Si:H single-junction and a-Si:H/μc-Si:H tandem solar cells have experimentally been conducted. The μc-Si:H single-junction solar cells with novel structure p-μc-SiO:H/ i-μc-Si:H/ n-SiO_x:H/ Ag/ Al were successfully fabricated on textured ZnO:B coated glasses by applying a newly developed n-SiO_x:H layer which works both as an n-layer and a back reflective ZnO layer. It was found that the spectral response at the long wavelength region was increased and then short-circuit current density (Jsc) was relatively increased up to 4.8%. Furthermore, our first a-Si:H/ μc-Si:H tandem solar cell with novel structure of p-a-SiC:H/ i-a-Si:H/ n-SiO_x:H/ p-μc-SiO:H/ i-μc-Si:H/ n-SiO_x:H/ Ag/ Al was also successfully prepared using plasma enhanced chemical vapor deposition (PECVD) technique. A high efficiency of 11.3% (Voc=1.36, Jsc=11.74 mA/cm², FF=0.71) was achieved. From these results, we can conclude that the solar cells with novel structure using newly developed n-SiO_x:H layers are a promising candidate for achieving higher efficiency.