Cross-sectional scanning tunnelling microscopy of III-V semiconductor structures

The method of cross-sectional scanning tunnelling microscopy (STM) is described. Illustrative examples are given of studies of III-V semiconductor systems, including Al_xGa_1-xAs/GaAs superlattices, InAs/GaSb superlattices and low-temperature-grown GaAs. Physical properties studied include alloy clustering, interface roughness, band offsets, quantum subbands and point defects. In each case, STM permits the observation of structural features on an atomic scale. The associated electronic spectroscopy for states a few eV on either side of the Fermi level can be determined. Such information is relevant for the operation of devices constructed from these layered semiconductor systems.