Broadband anti-reflection coating using dielectric Si3N4 nanostructures. Application to amorphous-Si-H solar cells

Abstract

Absorption of amorphous-Si hydrogenated (aSi-H) solar cells can be enhanced by using dielectric nanostructures made of Si3N4 that work like antireflection coatings. The analysis focus on the short-circuit current delivered by the cell under solar irradiance, and it is made taking into account every layer and structure of an aSi-H cell. A customized design of the antireflection coating in the form of nanostructured dielectric layers, produces a short-circuit current enhancement of 15.2% with respect to the reference flat solar cell, and a lower reflectivity of the cell. Three different geometries of linear nanostructures have been analyzed and compared with quite similar results among them. An improvement in performance has been also obtained for realizable geometrical dimensions that could be fabricated while maintaining electric conductivity of the front contact.