  We report a method to derive the potential barrier profile shape in a dynamic
quantum dot and show the loading statistics, and hence accuracy of electron
transfer, depend significantly on the shape of the barrier. This method takes a
further step towards tunable barrier shapes, which would greatly increase the
accuracy of single electron sources, allowing the single electron current to be
useful for quantum sensing, quantum information and metrology. We apply our
method to the case of a tunable-barrier single-electron pump, an exemplary
device that shows promise as a source of hot single electron wavepackets.

Mesoscale and Nanoscale Physics;Quantum Physics