Isolation and manipulation of a single-donor detector in a silicon quantum dot

We demonstrate the isolation and electrostatic control of a single phosphorus donor in a silicon quantum dot by making use of source-drain bias during cooldown and biases applied to capacitively coupled gates. Characterization of the device at low temperatures and in magnetic fields shows single donors can be electrostatically isolated near one of the quantum dot's tunnel barriers with either single or double occupancy. This model is well supported by capacitance-based simulations. The ability to use the D 0 state of such isolated donors as a charge detector is demonstrated by observing the charge stability diagram of a nearby and capacitively coupled semiconnected double quantum dot.