Current From Noise...

In this electron micrograph of the energy-harvesting device, the lower quantum dot is the red blob at the top of the red triangle. The upper quantum dot is the blue blob at the tip of the blue triangle. The image shows an area that is about 2 μm wide. (Courtesy: F Hartmann et al.)

Topics: Coupled Quantum Dots, Electronics, Quantum Mechanics, Thermodynamics

Two quantum dots have been used to generate an electrical current from voltage noise. The device was created by physicists in Germany, who say that it could lead to the development of systems that convert waste heat into useful energy.

Electronic devices generate large amounts of excess heat that must be dissipated. Instead of simply discarding this energy, using it to do useful work could revolutionize the electronics industry, and make it possible to create more efficient devices. Indeed, for more than a decade, physicists have been thinking up ways to convert this heat into electrical currents that can do work, such as power electronic devices.

Now, Lukas Worschech and colleagues at the University of Würzburg in Germany have verified experimentally that random voltage fluctuations can be rectified to drive a direct current. The experiment uses voltage noise to mimic the hot and cold spots of waste heat, and is therefore not a direct demonstration of waste heat being converted into work. However, team member Fabian Hartmann explains that it shows that small voltage fluctuations can drive a current: "A device derived from our sample might be able to provide the necessary power to drive autonomous and self-powered systems."

Physics World: Physicists generate electrical currents from noise,
Katherine Kornei