Atomic structure and luminescence excitation of GaAs/(AlAs) _n(GaAs)_m quantum wires with the scanning tunneling microscope

Abstract

We report on the imaging of a molecular beam epitaxially grown GaAs/(AlAs)n(GaAs)m quantum well-wire array by means of cross-sectional scanning tunneling microscopy (XSTM) and scanning tunneling-induced luminescence (STL). XSTM provides atomically resolved cross-sectional images of sets of quantum well wires with chemical sensitivity within the group III species and electrical sensitivity to single dopant atoms. This permits the precise observation of growth mechanisms and the identification of defects responsible for inhomogeneities in the growth morphology, as well as the determination of dopant incorporation throughout the structure. STL permits the relative quantum efficiency of individual quantum wires to be quantified.