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Silicon Surface Conductance Investigated Using a Multiple-Probe Scanning Tunneling Microscope

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Abstract

A custom-built multiple probe scanning tunneling microscope (STM) was used to perform measurements of the surface conductivity of Si(111)-7 × 7 and H-Si(111)-1 × 1 surfaces. Metallic contacts with points spaced <1 μm, deposited via electron-beam lithography, were used as contact points for two probes, while a central STM tip imaged the region between the contacts. A novel imaging method measuring the fraction of the tunneling current flowing to each contact was used to image surface conductivity with nanometer resolution. Si(111)-7 × 7 was shown to be significantly more conductive than H-Si(111)-1 × 1. Additionally, the resistance of single atomic steps on the Si(111)-7 × 7 was imaged using this method.

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Electrostatically Regulated Atomic Scale Electroconductivity Device (Patent filed 09
  • R A Wolkow