Si nanocone array optimization on crystalline Si thin films for solar energy harvesting

摘要

In this paper, the effects of structural parameters on the optical characteristics of crystalline Si thin films with the surface decorated by Si nanocone (SiNC) arrays are investigated by simulation. It is found that the SiNC base diameter should be equal to the array periodicity for efficient solar energy harvesting, and the optimized light absorption could already be realized when the SiNC height reaches ～400 nm. An ultimate efficiency of ～31.5% can be achieved when the periodicity is ～600 nm for an 800 nm thick Si film with a 400 nm high nanocone array although the total thickness is only 1200 nm. And the ultimate efficiency could be further increased to some extent due to the enhanced light absorption in the low energy region by appropriately increasing the Si film thickness. The underlying physics is also discussed in this work.