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Nanostructure Formation and Passivation of Large‐Area Black Silicon for Solar Cell Applications
Author(s) -
Liu Yaoping,
Lai Tao,
Li Hailing,
Wang Yan,
Mei Zengxia,
Liang Huili,
Li Zhilei,
Zhang Fengming,
Wang Wenjing,
Kuznetsov Andrej Yu,
Du Xiaolong
Publication year - 2012
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201101792
Subject(s) - passivation , black silicon , materials science , solar cell , silicon , anti reflective coating , nanostructure , carrier lifetime , etching (microfabrication) , energy conversion efficiency , crystalline silicon , optoelectronics , nanotechnology , isotropic etching , coating , layer (electronics)
Nanoscale textured silicon and its passivation are explored by simple low‐cost metal‐assisted chemical etching and thermal oxidation, and large‐area black silicon was fabricated both on single‐crystalline Si and multicrystalline Si for solar cell applications. When the Si surface was etched by HF/AgNO 3 solution for 4 or 5 min, nanopores formed in the Si surface, 50–100 nm in diameter and 200–300 nm deep. The nanoscale textured silicon surface turns into an effective medium with a gradually varying refractive index, which leads to the low reflectivity and black appearance of the samples. Mean reflectance was reduced to as low as 2% for crystalline Si and 4% for multicrystalline Si from 300 to 1000 nm, with no antireflective (AR) coating. A black‐etched multicrystalline‐Si of 156 mm × 156 mm was used to fabricate a primary solar cell with no surface passivation or AR coating. Its conversion efficiency ( η ) was 11.5%. The cell conversion efficiency was increased greatly by using surface passivation process, which proved very useful in suppressing excess carrier recombination on the nanostructured surface. Finally, a black m‐Si cell with efficiency of 15.8% was achieved by using SiO 2 and SiN X bilayer passivation structure, indicating that passivation plays a key role in large‐scale manufacture of black silicon solar cells.