Scanned probe imaging of quantum dots inside InAs nanowires.
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 nanowire--each 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 approximately 80 nm and lengths 2-3 microm.
Bleszynski
Ania C
AC
Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Zwanenburg
Floris A
FA
Westervelt
R M
RM
Roest
Aarnoud L
AL
Bakkers
Erik P A M
EP
Kouwenhoven
Leo P
LP
D001152:Arsenicals / Q000737:chemistry*; D004579:Electron Transport; D007204:Indium / Q000737:chemistry*; D008422:Materials Testing; D020527:Microscopy, Scanning Probe / Q000379:methods*; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D045663:Quantum Dots
D001152:Arsenicals; D007204:Indium; C076773:indium arsenide