Broadband anti-reflection coating for Si solar cell applications based on periodic Si nanopillar dimer arrays & Si₃N₄ layer

A structure of periodic Si nanopillar dimer array & Si 3 N 4 layer which sits on Si substrates is presented to obtain a broadband high transmission and low reflection. We show numerically that the average reflection of this structure can reach 1.8%, and the average transmission can reach 93.1% in the 400–1100 nm range, due to the combined effects of the forward scattering effects of Si nanopillar dimers and Si 3 N 4 layer’s anti-reflection effects. Si nanopillars’ diameter and height, Si 3 N 4 layer’s height, the gap of dimers, and the period of the array have significant impacts on the transmittance and reflection. This work supplies a practicable way for decreasing broadband surface reflection and increasing the absorption of light for Si solar cell applications.