A new proposal for Si tandem solar cell: Significant efficiency enhancement in 3C–SiC/Si

In order to considerable enhancement of the efficiency of silicon solar cells, in this paper, for the first time, we present a new proposal for silicon based tandem solar cells. For investigation of this idea, we have evaluated the characteristics of 3C–SiC/Si crystalline tandem solar cells connected series by a tunneling junction, under air mass 1.5 global irradiance spectrums. A 2D simulation including the effects of surface passivation, back surface field (BSF), and carrier tunneling have been performed to obtain the optical and electrical characteristics of single junction silicon, 3C–SiC, and finally the tandem cells. The obtained data illustrate that the best design parameters considering the experimental limitations can be obtained. High energy conversion efficiency for the proposed structure of 26.09% has been achieved for 3C–SiC/Si tandem structure driven by 20.49% and 17.86% conversion efficiencies of single junction Si and 3C–SiC solar cells, respectively. Our results justifies that the higher conversion efficiency of the Si-based tandem structure compared with 3C–SiC and Si cells stems from enhancement of open circuit voltage and fill factor parameter at the hands of decrease in short circuit current limited by the top 3C–SiC cell.