  Single-charge pumps are the main candidates for quantum-based standards of
the unit ampere because they can generate accurate and quantized electric
currents. In order to approach the metrological requirements in terms of both
accuracy and speed of operation, in the past decade there has been a focus on
semiconductor-based devices. The use of a variety of semiconductor materials
enables the universality of charge pump devices to be tested, a highly
desirable demonstration for metrology, with GaAs and Si pumps at the forefront
of these tests. Here, we show that pumping can be achieved in a yet unexplored
semiconductor, i.e. germanium. We realise a single-hole pump with a
tunable-barrier quantum dot electrostatically defined at a Ge/SiGe
heterostructure interface. We observe quantized current plateaux by driving the
system with a single sinusoidal drive up to a frequency of 100 MHz. The
operation of the prototype was affected by accidental formation of multiple
dots, probably due to disorder potential, and random charge fluctuations. We
suggest straightforward refinements of the fabrication process to improve pump
characteristics in future experiments.
