The essence of the research at Institute of Industrial Science, The University of Tokyo, is symbolically presented using a single verb.

Bounce back

In 1821, German physicist Thomas Seebeck discovered that when part of an electriccircuit is heated, the electric current flows toward the cooler part. This prompted a search for materials that can produce the highest voltage with a temperature difference of 1℃. But, materials with high electrical conductivity also tend to conduct heat, so the temperature difference is quickly lost.

To address this problem, Professor Masahiro Nomura and Project Associate Professor (at that time) Roman Anufriev focused on the phenomenon of heat behaving as particles and created a tiny pinball machine-like structure on a semiconductor to control the conductivity.

Holes placed across several hundred nanometers on the semiconductor wafer act like pins of a pinball machine. The holes bounce heat particles back as they travel in straight lines over relatively long distances, but not electrons as they incrementally change course.

This highly efficient thermoelectric conversion device, combined with a sensor, could have limitless applications. For example, slight temperature differences between sunny and shaded sides of a bridge could power automated bridge inspection devices.

Professor Masahiro Nomura