CROSS-SECTIONAL SCANNING-TUNNELING-MICROSCOPY OF ILL-V SEMICONDUCTOR STRUCTURES

The method of cross-sectional scanning tunnelling microscopy (STM) is described. Illustrative examples are given of studies of Ill-V semicon ductor systems, including AlxGa(1-x)As/GaAs superlattices, InAs/GaSb s uperlattices and low-temperature-grown GaAs. Physical properties studi ed include alloy clustering, interface roughness, band offsets, quantu m subbands and point defects. In each case, STM permits the observatio n of structural features on an atomic scale. The associated electronic spectroscopy for states a few eV on either side of the Fermi level ca n be determined. Such information is relevant for the operation of dev ices constructed from these layered semiconductor systems.