Large-area mask patterning for solar cell applications

摘要

Light harvesting using photonic crystal (PhC) surface patterns provides an opportunity to surpass the ray-opticsdefined light trapping and to approach thermodynamic ShockleyQueisser limit of solar cell efficiency, which fora single junction Si solar cell is ～32%. For an industry amenable nano-patterning of Si solar cells, we usedlaser direct write and stepper lithography based approaches for defining a large area (1 cm~2) light trapping PhCpatterns on silicon. Nanoholes of ～500 nm in diameter were fabricated by direct laser writing in a thin layerof chromium to act as a mask for subsequent reactive plasma etching to fabricate the nanostructures forming aPhC surface over a square centimeter. Surface area fabrication throughput was improved by more than order ofmagnitude as compared with electron beam lithography required to achieve sub-1 μm resolution.