Electron detection

An ammeter for nanoelectronic measurement has been developed in Japan that is so sensitive it can detect a single electron flowing in either direction in real time.

Nippon Telegraph and Telephone Corporation (NTT) collaborated with the Tokyo Institute of Technology (TokyoTech), the Japan Science and Technology Agency (JST), and Tohoku University to demonstrate the device. The single-electron ammeter can be used to measure extremely small currents undetectable to previous meters and to analyse the motion of an individual electron. It has potential applications in nanoelectronics and developing quantum information technologies.

A conventional sensitive ammeter requires the flow of millions of electrons in order to detect current. NTT’s single-electron ammeter integrates two quantum dots and a point contact in a semiconductor device. A quantum dot is a conductive nanostructure that accommodates a small number of electrons, in this case set so the number of electrons can change by only one.