Single molecule DNA device measured with triple-probe atomic force microscope

We have measured the electric properties of a three-terminal single molecul e DNA device with a triple-probe atomic force microscope (T-AFM). The T-AFM permits us to connect a single DNA molecule with carbon nanotube (CNT) ele ctrodes as source, drain, and gate terminals. As the gate bias voltage is i ncreased, the voltage gap region decreased in the current-voltage (I-V) cur ves. Furthermore, we can observe the clear steps in the I-V curve at crossi ng the DNA molecule and the CNT-gate electrode with gate biased. (C) 2001 A merican Institute of Physics.