Silicene has achieved rapid development due to its exotic electronic properties.Its low room-temperature mobility of~100 cm2·V-1s-1,however,inhibits device applications such as in field-effect transistors.Generally,defects 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 STM observations.The STM 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 defective appearance of √13 ×√13 silicene in experiments is explained.