High conversion efficiency of crystalline Si solar cells using black − Si fabricated by SSCT method

Abstract

We have developed a technology for fabrication of black − Si by use of the surface structure chemical transfer (SSCT) method. The ultralow reflectance below 3% results from formation of a graded porosity structure of a nanocrystalline Si layer formed by the SSCT method. The nanocrystalline Si layer with an extremely large surface area is effectively passivated by deposition of phosphosilicate glass (PSG) followed by heat treatment at 925 • C . After PSG passivation, the minority carrier lifetime greatly increases, and the internal quantum efficiency in the short wavelength region is also greatly increased. Using the SSCT method and the PSG passivation method, the high conversion efficiency of 19.7% is achieved.K e y w o r d s: surface structure chemical transfer, black Si, Si solar cells, surface passivation, reflectance, phosphosilicate glass

Optical properties of electrochemically etched N-type silicon wafers for solar cell applications

“…There are several technological processes of chemical surface treatment of silicon, while the most commonly used technological processes currently are electrochemical etching, stain etching, metal-assisted chemical etching, reactive ion etching, surface structure chemical transfer (SSCT), anisotropic wet etching, etc [4][5][6][7][8]. The result of these technological processes are different structures (porous structure, pyramidal structure, nanocrystalline structure) with different properties.…”