Nanostructure Formation and Passivation of Large‐Area Black Silicon for Solar Cell Applications

Abstract

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.

An effective way to simultaneous realization of excellent optical and electrical performance in large‐scale Si nano/microstructures

“…Moreover, it is of great significance that the τ ave exhibits a notable increment with the increase of α (corresponding to the increasing SiNWs length less than 1200 nm) for the fixed ALD cycles 100, 250, or 400 (framed by the dashed‐line ellipse), which is a very novel electrical characteristic and acts totally contrary to the regular SiNWs . This unique new finding indicates that the longer SiNWs (less than 1200 nm) can support lower surface recombination, opening a new way to simultaneously realize both the minimal optical and electrical losses .…”

One-step-MACE nano/microstructures for high-efficient large-size multicrystalline Si solar cells

“…Using the one-step MACE, Liu et al, [28] have achieved an η of 15.8% on mc-Si nanostructures based 156 Â 156 mm 2 solar cells with a stack passivation of SiO 2 /SiN x . Hsu et al, [29] have further improved the η to 16.38% for the 6'' one-step MACE mc-Si nanostructures based solar cells.…”

Realizing a facile and environmental-friendly fabrication of high-performance multi-crystalline silicon solar cells by employing ZnO nanostructures and an Al2O3 passivation layer

“…Unfortunately, the MCE technique is [001] oriented silicon preferred15161718, which is not very effective on the mc -Si surface. Because the formed Si NS is unable to distribute homogeneously on the surface owning to the random crystalline characteristic of the mc -Si, the light trapping ability will be degrade19. Meanwhile, the AgNO 3 contained in the etching solution is not cost effective.…”