Resistive switching effects in single metallic tunneling junction with nanometer-scale gap

We fabricated a single tunneling junction with a nanometer-scale gap between Pt electrodes. We found that the gap distance became smaller after a current sweep, which was presumably caused by the migration of the Pt atoms at the anode. The junction showed a reproducible negative differential resistance characteristic after reduction in the gap. The junction also showed resistive switching characteristics with a resistance ratio of over 100 by applying voltage of different waveforms. The tunneling area and gap distance for on/off-state were quantitatively estimated by fitting the measured characteristics to the simple model as 100 nm^2 and 0.8/1.2 nm, respectively

Piezoresistive properties of carbon nanotubes under radial force investigated by atomic force microscopy

We investigated the piezoresistive properties of single-wall carbon nanotubes (SWCNTs) under the tip-induced force in the radial direction using atomic force microscopy. We found that the conductance of the bundled SWCNTs was modulated by the applied radial force. The polarity and amount of the conductance change were different on every bundle and even dependent on the location where the force was applied. These phenomena were explained by the modulation of the band structures of the SWCNTs, which was caused by the deformation at the critical pressure

Local potential profiling of operating carbon nanotube transistor using frequency-modulation high-frequency electrostatic force microscopy

The local potential measurement of an operating carbon nanotube transistor provides information on the defects in the nanotube and the interfacial potential barriers. While Kelvin-probe force microscopy is a powerful technique to measure the local surface potential, its accuracy is often degraded by the charges trapped on the surrounding insulator surface. Here, we introduce an alternative method to measure the local potential profile along the nanotube being less affected by those charges. We identified the location of a defect and detected the variation in the potential profile for different gate bias voltages, which were not detected by the conventional method