Low Temperature Physics: 37, 856 (2011); https://doi.org/10.1063/1.3672008 (10 pages)
Физика Низких Температур: Том 37, Выпуск 9-10 (Сентябрь 2011), c. 1073-1084    ( к оглавлению , назад )

Surface and electron structure of the 6H-SiC(0001)-(3×3) surface and ultrathin Ag films on Si(111) and Si(001)

V.A. Gasparov

Institute of Solid State Physics RAS, Chernogolovka, Moscow district 142432, Russian Federation
E-mail: vgasparo@issp.ac.ru

Received February 23, 2011

Аннотация

Surface topographic (LEED, STM) and spectroscopic (ARUPS, XPS, STS) studies have been performed on the Si-terminated 6H-SiC(0001)-(3×3) surface and Ag superstructures and ultrathin films on Si(001) and Si(111) surfaces, using a scanning tunneling microscope (STM) in ultrahigh vacuum. Our results confirm that a 2D epitaxial metal growth is favored on Si(001) at low temperatures and a solid, two-domain Ag(111) film has been achieved at coverage’s as low as 10 ML. We have found that the films reveal a morphology with 3-dimensional features and with well defined honeycomb structure in between. An atomically flat Si(111)/Ag-(√3̅×√3̅)R30° surface has been modified by use of a scanning tunneling microscope (STM) in ultrahigh vacuum (UHV). High quality 6H-SiC(0001)-(3×3) and Si(111)-Ag(√3̅×√3̅)R30° over structures have been prepared and studied by means of ARUPS, XPS and LEED. The local density of states proportional to the normalized differential conductivity (dI / dV )/(I / V ) vs V spectra show a distinct bands of empty (–0.6 eV) and filled (0.65 eV) sites separated by 1.2 eV, for both areas. The results support a Mott–Hubbard-type model as used for the calculation of the density of states of 6H-SiC(0001)-(3×3) surface with Hubbard gap 1 eV.

PACS: 62.23.Eg Nanodots;
PACS: 68.35.B– Structure of clean surfaces (and surface reconstruction);
PACS: 68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM);
PACS: 73.40.–c Electronic transport in interface structures.

Ключевые слова: low-energy electron diffraction, visible ultraviolet and x-ray photoelectron spectroscopy, scanning tunneling spectroscopy, surface electrical transport (surface conductivity, surface recombination, etc.), silicon, silver.