One ampere corresponds to the flux of approx. 6 × 1018 electrons per second. By counting the electrons, the ampere can be traced to the second. The precondition for this is that the charge of an electron is exactly known or fixed, as planned in the new SI. For this purpose, single-electron pumps are developed in semiconductor structures in order to realize a precise electrical current by electron counting.
Single-electron pumps in semiconductor structures
Working Group 2.53: Low-dimensional Electron Systems
Arbeitsgruppe 2.53: Niedrigdimensionale Elektronensysteme