Photos: Transistors powered by single electrons

Scientists from the National Institute of Standards and Technology and NTT Corp. of Japan have demonstrated the first reproducible, controllable silicon transistors that are turned on and off by the motion of individual electrons.

This colorized micrograph shows three tunable gates across an electrical channel in a single electron tunneling (SET) transistor.

The images here show how tuning the voltage of the three gates controls very small amounts of electrical charge and regulates current flow in the new silicon transistor.

In the first figure, the pattern of diagonal lines indicates the charge is correlated throughout the device and current is flowing at levels ranging from 0 amps, shown in red, to 1.4 nanoamps, shown in violet. The next three figures show what happens as the voltage applied to the center gate is reduced. In the last figure, the square pattern indicates the charge has separated in the device, and the large amount of white space indicates a related drop-off in current.