Synthesis of Boron Nanosheets in Copper Medium

Boron has a tendency to form bulk structures due to its unique electron-deficient property, so it's hard for boron to form sheets in large quantities. Here, we report a novel method for the preparation of boron nanosheets in large quantities by copper medium. The method mainly includes mechanical exfoliation, recombination and extraction. A large number of boron nanosheets with a height of below 6 nm have been prepared in this work. X-ray photoelectron spectroscopy and Raman spectroscopy results confirmed that the nanosheets possess the characteristics of α-rhombohedra boron and β-rhombohedra boron with a high content of boron. Hexagonal and rhombic sheets have been observed and two different growth processes are revealed successfully, which are also the basic structures of boron nanosheets. An interesting phenomenon also have been discovered that high density nanotwins exist in β-Rhombohedra boron sheets and it might stimulate more interest in growth of nanomaterials.