posted on 2021-07-21, 13:03authored byPeizong Chen, Ningning Zhang, Kun Peng, Lijian Zhang, Jia Yan, Zuimin Jiang, Zhenyang Zhong
Artificial
graphene (AG) based on a honeycomb lattice of semiconductor
quantum dots (QDs) has been of great interest for exploration and
applications of massless Dirac Fermions in semiconductors thanks to
the tunable interplay between the carrier interactions and the honeycomb
topology. Here, an innovative strategy to realize AG on Si substrates
is developed by fabricating a honeycomb lattice of Au nanodisks on
a Si/GeSi quantum well. The lateral potential modulation induced by
the nanoscale Au/Si Schottky junction results in the formation of
quantum dots arranged in a honeycomb lattice to form AG. Nonlinear
current–voltage curves of the AG reveal conductance phase transitions
with switch on/off voltages, a large electric hysteresis loop, and
a strong sharp current peak accompanied by a group of differential-conductance
peaks and negative differential conductance around the switch-on voltage,
which can be modulated by temperature and light. These features are
interpreted by a model based on the Coulomb blockade effect, the collective
resonant tunneling, and the coupling of holes in the AG. Our results
not only demonstrate an approach to the formation but also will greatly
stimulate the characterizations and the applications of innovative
semiconductor-based AG.