Nanopurification of Silicon from 84% to 99.999% Purity with a Simple and Scalable Process
Nanopurification of silicon from 84% to 99.999% purity with a simple and scalable process Linqi Zonga, Bin Zhua, Zhenda Lub, Yingling Tana, Yan Jina, Nian Liub, Yue Hua, Shuai Gua, Jia Zhua,1, and Yi Cuib,c,1 aNational Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China; bDepartment of Materials Science and Engineering, Stanford University, Stanford, CA 94305; and cStanford Institute for Materials and Energy Sciences, Stanford Linear Accelerator Center National Accelerator Laboratory, Menlo Park, CA 94025 Edited by Charles M. Lieber, Harvard University, Cambridge, MA, and approved September 18, 2015 (received for review July 2, 2015) Silicon, with its great abundance and mature infrastructure, is a need from low-grade silicon is of high energy consumption and foundational material for a range of applications, such as elec- heavy pollution. Purification processes of Si typically involve the tronics, sensors, solar cells, batteries, and thermoelectrics. These conversion of Si into volatile liquids (such as trichlorosilane or Si applications rely on the purification of Si to different levels. Recently, tetrachloride) or gaseous silane (30). The compounds are then it has been shown that nanosized silicon can offer additional separated by a distillation and transformed into high-purity Si by advantages, such as enhanced mechanical properties, significant either a redox reaction or chemical decomposition at high absorption enhancement, and reduced thermal conductivity. How- temperatures. Additional steps are needed to obtain the nano- ever, current processes to produce and purify Si are complex, ex- structures of Si by either top-down methods, such as lithography, pensive, and energy-intensive.
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