Broadband Absorption Enhancement in μc-Si:H Thin-Film Solar Cells Based on Silver Nanoparticle Arrays

The thin-film solar cell structure with a broadband absorption enhancement is reported. We designed spherical silver (Ag) nanoparticle arrays on or embedded partially into indium tin oxide (ITO) layer of the hydrogenated microcrystalline silicon (μc-Si:H) thin-film solar cells. The geometrical parameters, such as nanoparticle radius (R), array period (P) and ITO layer thickness (d) are optimized by using the finite element method (FEM). The numerical results show that the key parameter that influences the integrated absorption is period/radius ratio (P/R) for Ag nanoparticle arrays. Embedding nanoparticle arrays partially into ITO layer with the appropriate thickness can improve broadband light-trapping. The optimized structure shows 50.1% enhancement in the integrated absorption compared to the reference cell when P=500nm, R=100nm and d=70nm. Furthermore, physical mechanisms of absorption enhancement in different wavelength range are discussed according to the electrical field amplitude distributions in ...