Characteristics of Carrier Collection of Nanopillar-Patterned Silicon Solar Cells

Nanopillar-patterned Si solar cells were investigated. Ag nanoparticles were coated on a polished Si substrate as an etching mask. Reactive ion etching caused Si nanopillars to replicate in a reverse fashion on the Ag nanoparticles over a large area. The nanopillar structures efficiently reduced the light reflection on the surface and effectively drove the incident light into a Si absorber. This induced a significant enhancement of the photogenerated-current with an improved solar cell efficiency of 16.07%. The Si nanopillar-patterned solar cells showed improved carrier collection for long wavelengths; however, the surface-defect induced recombination degraded the quantum efficiency at short wavelengths. We suggest that the reduction of recombination loss should be considered for efficient nanostructure solar cells.