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 & Si3N4 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 Si3N4 layer's anti-reflection effects. Si nanopillars' diameter and height, Si3N4 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.