Si nanopillar array optimization on Si thin films for solar energy harvesting

In this letter, Si thin film (800 nm thick) with nanopillar array decorated surface is studied via simulation for its solar energy absorption characteristics. It is found that the light absorption is significantly enhanced due to the adding of the Si nanopillar (SiNP) array to the Si thin film. The absorption characteristics of the SiNP structure would be approximately optimum (especially at similar to 2.5 eV, the high energy density region in the solar spectrum) when the periodicity of SiNP array is set as similar to 500 nm, which can be explained when comparing the incident light wavelength with the periodicity of SiNP array.