Characterization of hybrid metal/semiconductor electron pumps for quantum metrology

We present measurements of the quantized current delivered by a hybrid metal/semiconductor electron pump. Here we report on the dependence of the quantized current as a function of various control parameters at temperatures below 1 K. This characterization was done with a 20000 turns cryogenic current comparator (CCC) in internal feedback mode. Stability measurements over more than 10 hours have demonstrated a relative type A standard uncertainty of 4 parts in 10⁶. To benefit from the high accuracy of the CCC, we are currently improving the traceability of the current measurement.