Theoretical investigation on the absorption enhancement of the crystalline silicon solar cells by pyramid texture coated with SiN_x:H layer

摘要

The absorption enhancement of the crystalline silicon (c-Si) solar cells by pyramid texture coated with SiN_x:H layer was investigated by theoretical simulation via rigorous coupled-wave analysis (RCWA). It was found that in order to maximize the spectrally weighted absorptance of the solar cells for the Air Mass 1.5 (AM1.5) solar spectrum (A_(AM1.5)), the required pyramid size (d) was dependent on the thickness of the c-Si substrate. The thinner the c-Si substrate is, the larger the pyramids should be. Pyramids with d> 0.5 μm can make A_(am1.5) maximal if the c-Si substrate thickness is larger than 50 μm. But d> 1.0 um is needed when the c-Si substrate thickness is less than 25 μm. If the c-Si substrate is thinner than 5 μm, even d> 4.0 μm is required. The underlying mechanism was analyzed according to the diffraction theory. The pyramid texture acts as not only an antireflective (AR) component, but also a light trapping element. Then, the optimized refractive index and the thickness of SiN_x:H layer to further enhance the absorption were given out. The potential solar cell efficiency was also estimated.