  Quantum confined devices of three-dimensional topological insulators have
been proposed to be promising and of great importance for studies of confined
topological states and for applications in low energy-dissipative spintronics
and quantum information processing. The absence of energy gap on the TI surface
limits the experimental realization of a quantum confined system in
three-dimensional topological insulators. This communication reports on the
successful realization of single-electron transistor devices in Bi$_2$Te$_3$
nanoplates by state of the art nanofabrication techniques. Each device consists
of a confined central island, two narrow constrictions that connect the central
island to the source and drain, and surrounding gates. Low-temperature
transport measurements demonstrate that the two narrow constrictions function
as tunneling junctions and the device shows well-defined Coulomb current
oscillations and Coulomb diamond shaped charge stability diagrams. This work
provides a controllable and reproducible way to form quantum confined systems
in three-dimensional topological insulators, which should greatly stimulate
research towards confined topological states, low energy-dissipative devices
and quantum information processing.
