Dual-probe scanning tunneling microscope: Measuring a carbon nanotube ring transistor

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