Black silicon is a kind of silicon material with low reflection, comparing with conventional silicon material, black silicon exhibits strong light absorption capability and can be used in solar cells industry. In mid-June, researcher Xia Yang and his team in the Key Laboratory of Microelectronics Devices & Integrated Technology in Institute of Microelectronics of the Chinese Academy of Sciences (IMECAS) firstly proposed to produce black silicon by using plasma immersion ion implantation (PIII) technology.　

The microstructure, optical absorbance and lifetime of minority carriers of the black silicon were characterized by scanning electron microscopy (SEM), UV-VIS-NIR spectrophotometer and microwave photoconductive decay (μ-PCD), respectively. The results show that the black silicon has a porous structure. The average absorbance of the black silicon is above 94% in the visible region. The average lifetime of minority carriers in the black silicon is 5.68 μs. The effect of immersion parameters on the black silicon was investigated. It is found that the gas flux ratio of SF_6 to O_2 plays an important role in the microstructure and properties, and its optimum value is 2.80. The average reflection of the black silicon is 0.5% in visible wavelength region, which can compare with the black silicon achieved by irradiating femtosecond laser pulses. Meanwhile, PIII, as a low cost and high efficiency process, is more proposed for mass production. The relevant research papers are published on the journal of Solar Energy, Energy Procedia, Journal of Electron Spectroscopy and Related Phenomena, Acta Physica Sinica and so on. The project team also applied for more than 30 patents.　

By optimizing the textured structure and following-up process, researchers obtained 17.46% average efficiency solar cells based on PIII textured 156mm×156mm multicrystal silicon, and the highest efficiency of solar cells is up to 17.65% in this patch.
 

Black Silicon with Low Reflection (Image by IMECAS)

High Efficiency Multicrystal Black Silicon Solar Cells (Image by IMECAS)

Micro-Cones Structure of the Black Silicon  (Image by IMECAS)

Related Papers Published:
Solar Energy (Volume 85, Issue 7, July 2011, Pages 1574–1578)
Journal of Electron Spectroscopy and Related Phenomena (Volume 184, Issues 11–12, January 2012, Pages 589–592)
Research & Progress of SSE(2011-04)
Acta Physica Sinica (2012, Vol. 61 Issue (14): 0148102 )

RESEARCHER CONTACT:
Researcher XIA Yang
Institute of Microelectronics of Chinese Academy of Sciences
E-mail: xiayang@ime.ac.cn
Website of Dept.:
http://english.ime.cas.cn/Research/ResearchDivisions/LAB8/