Electric field modulation spectroscopy by scanning tunneling microscopy with a nanometer-scale resolution

Instrumentation has been devised by coupling electric field modulation spectroscopy (EFMS) with scanning tunneling microscopy (STM) that enables the investigation of electronic band structures in semiconductors with a nanometer-scale spatial resolution. Model experiments using low-temperature-grown GaAs (LT-GaAs) epifilms show that a difference as small as 0.01 eV in electronic energy gaps between the GaAs substrate and the LT-GaAs epilayers can be distinguished in the EFMS spectra, demonstrating the high energy, as well as spatial, resolution of the STM-EFMS. (C) 2001 American Institute of Physics.