High transmission nanowire contact arrays with subwavelength spacing

Abstract

We demonstrate high optical transmission in solar cell contacts based on nanowire arrays with subwavelength spacing. The photocurrent results obtained from fabricated devices are compared with numerical simulations. The proposed contact design leads to optical losses significantly smaller than the fraction of the top surface taken up by the metallic contact (<10% vs. 36%). The resulting sheet resistance of the contact is 46.7 Ω/square, comparing favourably with transparent conductive oxides. Normalized electric field magnitude at λ = 887 nm, polarization perpendicular to the nanowires. The black contours indicate the position of the nanowires and the GaAs surface. The reflected wave‐front is undisturbed by the subwavelength array (period = 250 nm), but the transmitted light is strongly scattered in a Talbot effect pattern.