Dual-probe scanning tunneling microscope: Measuring a carbon nanotube ringtransistor

We have constructed a dual-probe scanning tunneling microscope (D-STM). We used multiwall carbon nanotubes [(NT), diameter: similar to 10 nm] as STM p robes. The D-STM allows us to elucidate the electric property of a sample w ith a spatial resolution of similar to1 nm. Using this system, we have meas ured the current-voltage curves of a single NT ring as a transistor. The cu rves show the possibility of nanometer-scale electronic circuits composed o f NT devices. (C) 2001 American Institute of Physics.