Electrical transport through a scanning tunnelling microscope tip and a heavily doped Si contact

By allowing the metallic tip of a scanning tunnelling microscope to penetrate a Si(111) sample at 5 K, we found that the electrical transport through the tip and the heavily doped Si(111) contact undergoes a transition from rectifying to ohmic behavior. This transition does not occur when the tip penetrates a moderately doped Si(111). This observed ohmic behavior when the Si(111) is heavily doped is semi-quantitatively simulated only by a vanishingly small Schottky barrier height, suggesting that the Schottky barrier height can be affected by the doping concentration in the semiconductor. (C) 2013 AIP Publishing LLC