  We report on the observation of periodic conductance oscillations near
quantum Hall plateaus in suspended graphene nanoribbons. They are attributed to
single quantum dots that form in the narrowest part of the ribbon, in the
valleys and hills of a disorder potential. In a wide flake with two gates, a
double-dot system's signature has been observed. Electrostatic confinement is
enabled in single-layer graphene due to the gaps that form between Landau
levels, suggesting a way to create gate-defined quantum dots that can be
accessed with quantum Hall edge states.
