  Deterministic control over the location and number of donors is crucial to
donor spin quantum bits (qubits) in semiconductor based quantum computing. In
this work, a focused ion beam is used to implant antimony donors close to
quantum dots. Ion detectors are integrated next to the quantum dots to sense
the implants. The numbers of donors implanted can be counted to a precision of
a single ion. In low-temperature transport measurements, regular coulomb
blockade is observed from the quantum dots. Charge offsets indicative of donor
ionization are also observed in devices with counted donor implants.
