A combination of an atomic force microscope (AFM), scanning tunneling microscope (STM) and field ion microscope (FIM), which is unique worldwide so far, is used to characterize and manipulate samples and tips on an atomic scale. These microscopes are incorporated in a ultra high vacuum surface science system to achieve control over the cleanliness of the sample and tip. Samples are prepared and characterized in a UHV sample preparation chamber using a UHV evaporator and Scanning Auger Microscope.
In our first proposed experiment, one contacting wire is an atomically characterized (by STM) surface, while the second contact is made by the field ion microscopy (FIM) characterized tip. The power of this approach is that there are no fudge parameters when comparing experimental results to modeling. We plan to investigate the pressure dependent conductance of organic molecules. The pressure can directly be calculated from the known tip size and the measured applied force. The aim is to find a molecule that has the largest amplification gain for the smallest amount of pressure change. This will be achieved by performing experiments on a few simple molecules such as C60, benzene, porphyrins or alkane thiols. In the future local pressure changes could be brought about by (light activated) confirmation changes of gate molecules.
The instruments are housed in a three chamber ultra-high vacuum system with a quick load lock chamber, sample preparation chamber, and measurement chamber. Pictures of the complete system can be found here.
D. J. Oliver, W. Paul, M. El Ouali, T. Hagedorn, Y. Miyahara, Y. Qi, and P. Grütter
"One-to-one spatially matched experiment and atomistic simulations of nanometre-scale indentation"
Nanotechnology 25, 025701 (2014)
W. Paul, D. Oliver, Y. Miyahara, and P. Grütter
Nanotechnology 24, 475704 (2013)
W. Paul, D. Oliver, Y. Miyahara, and P. Grütter
"Minimum Threshold for Incipient Plasticity in the Atomic-Scale Nanoindentation of Au(111)"
Phys. Rev. Lett. 110, 135506 (2013)
W. Paul, Y. Miyahara, and P. Grütter
"Simple Si (111) surface preparation by thin wafer cleavage"
J. Vac. Sci. Technol. A 31, 023201 (2013)
D. J. Oliver, J. Maassen, M. El Ouali, W. Paul, T. Hagedorn, Y. Miyahara, Y. Qi, H. Guo, and P. Grütter
"Conductivity of an atomically defined metallic interface"
Proc. Natl. Acad. Sci. U. S. A. 109, 19097 (2012); doi:10.1073/pnas.1208699109
W. Paul, Y. Miyahara, and P. Grütter
"Implementation of atomically defined field ion microscopy tips in scanning probe microscopy"
Nanotechnology 23 335702 (2012); doi:10.1088/0957-4484/23/33/335702
T. Hagedorn, M. El Ouali, W. Paul, D. Oliver, Y. Miyahara, and P. H. Grütter
Rev. Sci. Instrum. 82, 113903 (2011)
J.-B. Lalanne, W. Paul, D. Oliver, and P. H. Grütter
"Note: Electrochemical etching of sharp iridium tips"
Rev. Sci. Instrum. 82, 116105 (2011)
UHV chamber
FIM group: Mehdi, Will, Till, Peter, David, Yoichi