  Quantum confined devices that manipulate single electrons in graphene are
emerging as attractive candidates for nanoelectronics applications. Previous
experiments have employed etched graphene nanostructures, but edge and
substrate disorder severely limit device functionality. Here we present a
technique that builds quantum confined structures in suspended bilayer graphene
with tunnel barriers defined by external electric fields that break layer
inversion symmetry, thereby eliminating both edge and substrate disorder. We
report clean quantum dot formation in two regimes: at zero magnetic field B
using the single particle energy gap induced by a perpendicular electric field
and at B > 0 using the quantum Hall ferromagnet {\nu} = 0 gap for confinement.
Coulomb blockade oscillations exhibit periodicity consistent with electrostatic
simulations based on local top gate geometry, a direct demonstration of local
control over the band structure of graphene. This technology integrates single
electron transport with high device quality and access to vibrational modes,
enabling broad applications from electromechanical sensors to quantum bits.
