Surface roughness and electrical resistance on Si(1 0 0)2×3-Na surface

Using scanning tunneling microscopy, reflection-high-energy-electron diffraction and in situ electrical-resistance measurements, we studied the relation between surface morphology and electrical resistance of a Si(1 0 0)2×3-Na surface phase. It was found that the step density and domain size of the 2×3-Na phase depended on Si coverages deposited prior to Na deposition, because the amount of Si atoms incorporated in the 2×3-Na phase is a definite value, 1/3 monolayer (ML). The evolution of surface morphology was found to influence the transport properties dramatically. The resistance was reduced for smoother surfaces with larger domains with the pre-deposited Si of around 1/3 or 4/3 ML, while it increased for rougher surfaces with the intermediate amounts of Si pre-deposition. These phenomena directly associate with carrier scattering due to surface roughness.