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论文类型： 期刊论文

发表时间： 2016-06-01

发表刊物： 2D MATERIALS

收录刊物： SCIE

卷号： 3

期号： 2

ISSN号： 2053-1583

关键字： silicene; point defect; DFT; STM

摘要： Silicene, a counterpart of graphene, has achieved rapid development due to its exotic electronic properties and excellent compatibility with the mature silicon-based semiconductor technology. Its low room-temperature mobility of similar to 100 cm(2) V-1 s(-1), however, inhibits device applications such as in field-effect transistors. Generally, defects and grain boundaries would act as scattering centers and thus reduce the carrier mobility. In this paper, the morphologies of various point defects in epitaxial silicene on Ag(111) surfaces have been systematically investigated using first-principles calculations combined with experimental scanning tunneling microscope (STM) observations. TheSTM signatures for various defects in epitaxial silicene on Ag(111) surface are identified. In particular, the formation energies of point defects in Ag(111)-supported silicene sheets show an interesting dependence on the superstructures, which, in turn, may have implications for controlling the defect density during the synthesis of silicene. Through estimating the concentrations of various point defects in different silicene superstructures, the mystery of the defective appearance of root 13 x root 13 and 2 root 3 x 2 root 3silicene in experiments is revealed, and 4x4 silicene sheet is thought to be the most suitable structure for future device applications.