Reduced Fresnel Reflection by Photon Tunneling in Antireflection Coating Layer of Crystalline Si Solar Cells

We investigated the light absorption of multi-antireflective layers on the microtextured surface of a crystalline silicon solar cell. Triple antireflection coating layers were deposited with SiNx/SiO2/SiNx thin films. A 20 nm SiO2 layer was sandwiched between two SiNx layers, forming a total thickness around 90 nm. Triple antireflection layers showed the enhanced light absorption in the infrared wavelength range, which is consistent with the Si energy band gap region. Further optical simulation on triple antireflection layers using a transfer matrix method showed similar reflection behavior to that of the experimental results. The SiO2 layer sandwiched between the SiNx thin films acts not only as the Fresnel reflection layer in the blue and UV spectral regions, but also as a photon tunneling layer in the infrared spectral region.