Electronic properties of semiconductor nanostructures probed by scanning tunneling microscopy

We demonstrate the novel application of the scanning tunneling microscope to find and probe the electronic transport properties of single semiconductor nanostructures at temperatures from room temperature to as low as 1.5 K. The current-voltage characteristics of InGaAs/InAlAs resonant tunneling nanostructures clearly show negative differential resistance. From the dependence of the current on cross-sectional area the lateral depletion is estimated to be 300 Å.