High-resolution potential mapping in semiconductor nanostructures by cross-sectional scanning tunneling microscopy and spectroscopy

Using a combination of scanning tunneling microscopy and spectroscopy techniques, and a series of periodic ?-doped structures in GaAs, we show that the electrostatic potential can be mapped along {110} cross sections in semiconductor nanostructures with nanometer resolution and 30 meV sensitivity. Our results also indicate that microscopic capacitors with plates spaced by as little as 2 nm can be implemented by ? doping for band gap engineering purposes.