Scanning probe microscope (SPM) in combination with transmission electron microscope (TEM), so called TEM-SPM , was used for adhesion and force interaction studies of metallic and semiconducting nanowires and nanocontacts. TEM-SPM is an attractive combined tool for direct investigation of the structure, electronic properties, and interactions in atomic scale. In TEM-SPM the size and shape of the tip and sample, as well as the size of contact area and the type of interaction (elastic/plastic), are observed directly.
In short, our TEM-SPM consists of a piezo tube which is used for fine motion, and of a geared stepping motor for rough z-motion. For force measurements we used an AFM cantilever. The force was measured by direct measurement of the displacement of the AFM tip. The TEM-SPM was inserted into a Philips CM200 field emission gun TEM. TEM-SPM was used to investigate force interactions between two gold samples and mechanical properties and force interactions of Si and Ge nanowires.
When approaching gold coated AFM tip to sharp Au tip an anomalous high value of the jump-to-contact distance was found. We ascribe this to an enhanced surface diffusion of gold atoms towards the tip-sample gap due to the van der Waals forces, leading to an avalanche situation where the gap is quickly filled until the ordinary jump-to-contact distance. Neck formation was observed in the gap between two nanocontacts during the jump to contact. It showed up when the gap between two gold nanoasperities was decreased below 1 nm.
The contact radius at zero applied loads were measured and compared with adhesion theories. The results were in the Maugis transition region, between the limiting cases of the Derjaguin-Müller-Toporov (DMT) and the Johnson-Kendall-Roberts (JKR) models.
Nanowire of diameter less than 1 nm was created in the gap between two Au nanocontacts by lateral AFM tip movement. The rupture force of Au nanowire was 9 nm, which corresponds to about 1 nN per atom.

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