Electrons observed

Researchers at the EPFL (Ecole Polytechnique Federale de Lausanne) have developed a new machine that can reveal how electrons behave inside a single nano-object. The results from initial tests on pyramidal gallium-arsenide quantum dots are presented in an article in the November 24 issue of Nature.

The machine in EPFL’s Laboratory of quantum optoelectronics took four years to perfect and represents an equipment investment of more than a million Swiss francs.

Contemporary methods used to explore material properties and dynamics run into limits when applied at the nanoscale. Current techniques either have good spatial resolution (down to tens of nanometres or below) or an ultrafast time resolution (down to picoseconds), but not both.

The machine developed by Professor Benoit Deveaud-Pledran and his EPFL colleagues is the first tool that can track the passage of an electron in a nanostructure, at a time scale of ten picoseconds and a spatial resolution of 50 nanometres.