Novel a-Si:H/μc-Si:H tandem cell with lower optical loss

Abstract We propose a novel a-Si:H/μc-Si:H tandem cell in order to lower optical losses by using the optimum n-SiO x :H layer as multi-functional layers. The μc-Si:H single-junction solar cell with novel structure was fabricated using this n-SiO x layer which serves both as an n-layer and a ZnO back reflective layer. With novel μc-Si:H solar cell structure a relative increase in J sc value up to 4.4% has been observed. In the same way, by employing the optimal n-SiO x :H layer into a novel a-Si:H/μc-Si:H tandem cell with 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 structure the relative improvement in total J sc value by 9% was obtained and therefore the initial efficiency as high as 11.9% ( V oc  = 1.38 V, J sc  = 12.24 mA/cm 2 , FF = 0.70) was achieved. Moreover, the improved spectral response of both top and bottom cells were also obtained. These results approved that in this novel structure the first layer of two dual-functional n-SiO x :H layers can work as an n-layer of the top cell and at the same time it can also be functioned as an intermediate layer. On the other hand, the second n-SiO x :H layer can work as an n-layer of the bottom cell and a ZnO back reflective layer. As a result, the reduction in optical losses could be obtained.