ZnO Nanorods with Broadband Antireflective Properties for Improved Light Management in Silicon Thin‐Film Solar Cells

Zinc oxide nanorod structures constitute a promising concept to improve light management in photovoltaic devices. This paper reports on the antireflective properties of zinc oxide nanorod arrays in hydrogenated amorphous silicon thin‐film solar cells. Arrays with different structure sizes, grown by electrochemical deposition on aluminum doped zinc oxide seed layers with different thicknesses (400 nm, 800 nm, 1200 nm), are compared. The results show a reduction in the average weighted cell reflectivity by up to 6.1%, as well as enhanced quantum efficiencies and short circuit current densities for all nanorod cells. Optical simulations, describing the nanorod arrays as an effective medium, show that refractive index grading is the main antireflective effect. The improved optical properties result in enhanced power‐conversion efficiencies, demonstrating the feasibility of the nanorod concept for different seed layer thickness and array structure sizes.