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Paper
Tunneling spectroscopy of the Si(111)2 × 1 surface
Abstract
Using a scanning tunneling microscope, the tunneling current versus voltage is measured at fixed values of separation between a tungsten probe-tip and a Si(111)2 × 1 surface. Rectification is observed in the I - V curves and is quantitatively accounted for by an electric-field enhancement due to the finite radius-of-curvature of the probe-tip. The parallel wave-vector of certain states is obtained from the decay length of the tunneling current. A rich spectrum is obtained in the ratio of differential to total conductivity, yielding a direct measure of the Si surface density-of-states. Small shifts are observed in the spectrum as a function of doping, and are attributed to shifts in the position of the surface Fermi level. © 1987.