Broadband triple-layer SiOx/SiOxNy/SiNx antireflective coatings in textured crystalline silicon solar cells

The purpose of this study is to reduce textured crystalline silicon (TCS) substrate surface-reflectivity over a wide spectral range (300-1100 nm), to improve the step coverage of the textured structure, and to shift the minimal value of reflection from the unabsorbed region to the absorbed region. The TCS solar-cell interface between air and silicon was added to a SiOx/SiOxNy/SiNx triple-layer anti-reflective coatings (TLARCs) structure using the plasma-enhanced chemical vapor deposition (PECVD) growth method. This paper presents theoretical and practical discussions, as well as the experimental results of fabricating the films and devices. The average reflection of the SiOx/SiOxNy/SiNx TLARs reduced to 2.01% (300-1100 nm). The minimal value of reflection was shifted from 1370 nm (unabsorbed region) to 968 nm (absorbed region). The SEM images show effective step coverage. In comparison to the untreated TCS solar cells, applying the experimental SiOx/SiOxNy/SiNx TLARCs to conventional TCS solar cells improved the short-circuit current density (J(sc)) by 7.78%, and solar-cell efficiency by 10.95%. This study demonstrates that the SiOx/SiOxNy/SiNx TLARCs structure provides antireflective properties over a broad range of visible and near-infrared light wavelengths. An effective step coverage and minimal value of reflection from unabsorbed region shift to the absorbed region is demonstrated. (C) 2013 Elsevier Ltd. All rights reserved.