Numerical simulation of the performance of dual junction a-Si:H/a-SiGe:H solar cell with AMPS-1D

The aim of this work was to design solar cells with dual junction amorphous silicon/amorphous silicon germanium (a-Si:H/a-Si_1-xGe_x:H) absorber structure. However, thin film solar cells still suffer lower conversion efficiency and need to be improved using innovative technologies. In the present work, p-a-Si:H, i-a-Si:H, i-a-Si_1-xGe_x:H and n-a-Si:H layer with the same band gaps of 1.8 eV, the thickness equal to 5 nm, 340 nm, 5 nm and 5 nm respectively, and acceptor and donor concentrations are constant and equal to 3×10¹⁹ cm^-3 and 1×10¹⁹ cm^-3, respectively, are optimized for obtaining efficient a-Si:H p-i-i-n solar cell by computer aided one-dimensional Analysis of Microelectronic and Photonic Structures (AMPS-1D) simulation program. To improve the performance of a-Si_1-xGe_x:H we investigate: i) the band gap effect of a-Si_1-xGe_x:H, ii) the thickness effect of a-Si_1-xGe_x:H on the conversion efficiency of solar cell. Simulation results show that considerable efficiency enhancement can be obtained.