Identification of Surface Defects and Subsurface Dopants in a Delta-Doped System Using Simultaneous nc-AFM/STM and DFT

We have studied the near surface defects of the delta-doped B:Si(111)-(√3 × √3)R30° system using a combination of scanning tunneling microscopy, non-contact atomic force microscopy, Kelvin probe force spectroscopy, total energy DFT, and STM theoretical simulations. We positively identify and characterize two near surface defects: the adatom vacancy and a B substitutional defect located in the second Si bilayer. We also confirm the assignment of the dangling-bond defect. Additionally, the influence that the subsurface B dopants have on the surface electronic structure, the modulation of the surface potential and the chemical activity of the surface is investigated.