Ultrathin nanodome solar cell incorporating an antireflection structure and metal grating

To explore the answer to the question of whether nanodome solar cells with an ultrathin (<40 nm) α-Si layer can achieve large active layer absorption or not, we use finite element methods to numerically simulate the EM field distribution of the proposed structure. By properly designing the geometrical parameters of the metal grating, we propose a structure for a nanodome solar cell with an α-Si layer thickness of only 26 nm, with calculation results showing the averaged active layer absorption is as high as 71.3%. We find and investigate three benefits of this nanodome solar cell, including reduced reflection in the short wavelength range, a blue-shifted Fabry–Perot resonance, which induces a good matching between the absorption spectrum and the solar spectrum, and an improved absorption spectrum in the long wavelength range. Also, the dependence of active layer absorption on structure symmetry and incidence angle is analyzed. For asymmetrical structures, the averaged active layer absorption is increased for the enhanced asymmetrical cavity modes, giving a largest absorption of 74.59% when the asymmetrical factor f is 0.17. For incident angles from 10° to 90°, the active layer absorption of the symmetrical proposed structure is enhanced on average by 112%. (paper)