STM and STS on single dopants and Au-induced chains at the Si(111) surface

The electronic properties of single P- and B-dopants at the cleaved Si(1 1 1) surface of Czochralski-grown single crystals are investigated by scanning tunneling microscopy (STM) and spectroscopy at room temperature. Both types of dopants (donors or acceptors) can be identified by a specific voltage-dependent image contrast. The local variation of the electronic structure is confirmed by tunneling spectra taken at and away from the dopant site. Furthermore, Au-induced chainlike structures on vicinal Si(1 1 1) substrates are prepared by deposition of submonolayer coverages of gold. The tunneling spectra exhibit distinct features on the different types of protrusions which suggests that they arise from different types of atoms, i.e. Si or Au. (C) 2003 Elsevier Science B.V. All rights reserved.