 |
 |
 |
 |
|
|||
|
|
 |
|
|
 |
||
 |
||||||
                  |
|
Physics Special Colloquium, March 1, 2005A microscopic view of single-electron charging in carbon nanotubes with non-contact AFMJun ZhuCornell UniversityScanned probe techniques have become essential tools in exploring physical properties of nanostructures thanks to their spatial resolution and spectroscopic capabilities. In this talk, I will report our investigations of single-electron charging phenomena in semiconducting carbon nanotubes using a low temperature Atomic Force Microscope. Several techniques, such as Scanned Gate Microscopy (SGM), Electrostatic Force Microscopy (EFM), and Frequency Modulation Microscopy (FMM) are employed. Spatial images show well-resolved quantum dots distributed along the nanotube. Coulomb oscillations appear as equipotential rings centered on each dot. Unlike transport measurements, EFM and FMM techniques do not require conduction through the whole device. This allows us to visualize spatially and energetically the charging process of a semiconducting tube as its Fermi energy is tuned from deeply p-regime, across the bandgap, into deeply n-regime, where the device as a whole shows no conduction. From FMM data we extract the important parameters of the quantum dots, including their size, charging energy, and couplings to the tip and the global backgate. 10:30 a.m., Room 1094 Smith LabRefreshments served at 10:00 a.m. |
|
 |
|
|
|
|
| |||||
|
|
|
||||||
|
|
|||||||
