Imaging of Local Tunneling Barrier Height of InAs Nanostructures Using Low-Temperature Scanning Tunneling Microscopy

摘要

The local tunneling barrier height (LTBH) has been measured using low-temperature scanning tunneling microscopy to examine the local potential profile of an InAs nanostructure. The nanostructure is a faultily-stacked nanocrystal in epitaxial InAs thin film grown on GaAs(111)A substrate. It is found that averaged LTBH is consistent with the workfunction or electron affinity of InAs. The nanostructure boundary is found to have a higher LTBH than the surroundings. The resonance peak calculated using this potential wall is comparable to that measured by spectroscopy of local density of states (LDOS) in the nanostructure. A gradual LTBH decrease is additionally observed at negative sample bias voltage near the boundary indicating downward band bending, which is consistent with LDOS there.