We demonstrate the possibility of engineering a single donor transistor
directly from a phosphorous doped quantum dot by making use of the intrinsic
glassy behaviour of the structure as well as the complex electron dynamics
during cooldown. Characterisation of the device at low temperatures and in
magnetic field shows single donors can be electrostatically isolated near one
of the tunnel barrier with either a single or a doubly occupancy. Such a model
is well supported by capacitance-based simulations. Ability of using the D0 of
such isolated donor as a charge detector is demonstrated by observing the
charge stability diagram of a nearby and capacitively coupled semi-connected
double quantum dot.Comment: 10 pages, supplementary information available on demand, new version
as accepted for publication in PR