This work was supported in part by DTRA and NSF under Grant Nos. CBET-0744879 and CMMI-1000686
Applied Physics Letters
Photovoltaic cells -- Research, Optical coatings, Silicon solar cells -- Analysis
The authors report a simple and scalable bottom-up technique for fabricating broadband antireflection gratings on solar-grade multicrystalline silicon (mc-Si) wafers. A Langmuir-Blodgett process is developed to assemble close-packed silica microspheres on rough mc-Si substrates. Subwavelength moth-eye pillars can then be patterned on mc-Si by using the silica microspheres as structural template. Hemispherical reflectance measurements show that the resulting mc-Si gratings exhibit near zero reflection for a wide range of wavelengths. Both experimental results and theoretical prediction using a rigorous coupled-wave analysis model show that close-packed moth-eye arrays exhibit better antireflection performance than non-close-packed arrays due to a smoother refractive index gradient.
Phillips, B. M., Jiang, P., & Jiang, B. (2011). Biomimetic broadband antireflection gratings on solar-grade multicrystalline silicon wafers. [Article]. Applied Physics Letters, 99(19), 3.