Rapid single-electron sensor has promise for quantum devices

A European team in Cambridge has designed a sensor that can detect the charge on a single electron in the fastest time ever recorded.

Researchers at the laboratory where the electron was discovered in the 19th century have designed a sensor that can detect the charge of a single electron in less than a microsecond. The sensor, which was designed at Cambridge University’s Cavendish Laboratory, could be used in quantum computing to detect information stored in a single electron’s charge or spin, the team says.

Called a gate sensor, the device gets its sensitivity through coupling to a silicon nanotransistor that forces electrons to flow effectively in single file, the team explains in Nature Communications.

“We have called it a gate sensor because, as well as detecting the movement of individual electrons, the device is able to control its flow as if it were an electronic gate which opens and closes,” explained lead researcher Fernando González Zalba of the Spanish Foundation for Science and Technology.

The new device is more compact and accurate than previous gate sensors, Gonzalez Zalba said. The detection speed of around a nanosecond is the fastest obtained so far for this type of system.

Devices such as ultra-precise biosensors, single electron transistors, molecular-scale circuits and quantum computers are all predicted to work by using the properties of individual electrons to carry data, rather than the flow of many electrons as is the case with current systems.