  The discovery of topological insulators (TIs) and their unique electronic
properties has motivated research into a variety of applications, including
quantum computing. It has been proposed that TI surface states will be
energetically discretized in a quantum dot nanoparticle. These discretized
states could then be used as basis states for a qubit that is more resistant to
decoherence. In this work, prototypical TI Bi2Se3 nanoparticles are grown on
GaAs (001) using the droplet epitaxy technique, and we demonstrate the control
of nanoparticle height, area, and density by changing the duration of bismuth
deposition and substrate temperature. Within the growth window studied,
nanoparticles ranged from 5-15 nm tall with an 8-18nm equivalent circular
radius, and the density could be relatively well controlled by changing the
substrate temperature and bismuth deposition time.
