We show how a scanning probe microscope (SPM) can be used to image electron flow through InAs nanowires, elucidating the physics of nanowire devices on a local scale. A charged SPM tip is used as a movable gate. Images of nanowire conductance versus tip position spatially map the conductance of InAs nanowires at liquid-He temperatures. Plots of conductance versus backgate voltage without the tip present show complex patterns of Coulomb-blockade peaks. Images of nanowire conductance identify their source as multiple quantum dots formed by disorder along the nanowireseach dot is surrounded by a series of concentric rings corresponding to Coulomb blockade peaks. An SPM image locates the dots and provides information about their size. In this way, SPM images can be used to understand the features that control transport through nanowires. The nanowires were grown from metal catalyst particles and have diameters ∼80 nm and lengths 2−3 μm. An explosion in research activity on semiconducting nanowires has occurred in the past decade. 1-3 The ability to control the dimensions and composition of nanowire devices shows great promise for nanoelectronics, nanophotonics, and quantum information processing. Quantum effects are naturally important due to their small size, opening new possibilitie
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