Spectroscopy of positively and negatively buckled domains on Si(111)-2×1

Electronic disorder of P- and B-doped Si at the metal–insulator transition investigated by scanning tunnelling microscopy and electronic transport

“…The difference is in qualitative agreement with the results from Busetti et al [18]. A similar reduction of the bandwidth was obtained from ab initio calculations [19]. The high density of surface states and the heavy doping of Si:P also give rise to a charge accumulation at the surface and a space charge that subsides into volume within a depth of 9-10 nm, slightly depending on the type of buckling [19].…”

“…Hence, occupied (unoccupied) electronic states are imaged at negative (positive) tunnelling voltage V . as well as at RT [18,19]. It has been argued that the relative abundances of the isomers depend on the size of the isomer domains and on the doping level due to a charge transfer between the domains [20].…”

“…It has been argued that the relative abundances of the isomers depend on the size of the isomer domains and on the doping level due to a charge transfer between the domains [20]. For the two types of buckling, the relative positions of the surface bands in the band gap of bulk Si were determined by STS with high lateral resolution [19]. The geometric arrangement of the atomic cores at the 2 × 1 surface has been obtained from ab initio calculations [21].…”

“…In addition, different types of antiphase boundaries exist at the Si(111)-2 × 1 surface [30,37]. Their location can be manipulated by the STM tip, allowing a control of strain at the atomic scale [19,37].…”

“…The different types of buckling affect the bandgaps at the surface and the depths of the space charge layer. Due to the heavy doping and the presence of surface states at the surface, the Fermi level E F is pinned just at the lower edge of the surface conduction band [19,32]. The bandgap of the π-bonded chains has a width of 0.52 and 0.29 eV for positive and negative buckling, respectively.…”