An illustration of
the strong valley exciton interactions and transport in a
2-D semiconductor
heterostructurePasqual Rivera, Kyle Seyler
(February 12, 2016) Heterostructures
formed by different three-dimensional semiconductors form the foundation for modern
electronic and photonic devices. Now, University of Washington scientists have
successfully combined two different ultrathin semiconductors — each just one
layer of atoms thick and roughly 100,000 times thinner than a human hair — to
make a new two-dimensional heterostructure with potential uses in clean energy
and optically-active electronics. The team, led by Boeing Distinguished
Associate Professor Xiaodong Xu, announced its findings in a paper published
Feb. 12 in the journal Science.
Senior author Xu and lead authors Kyle Seyler and Pasqual
Rivera, both doctoral students in the UW physics department, synthesized and
investigated the optical properties of this new type of semiconductor sandwich.
“What we’re seeing here is distinct from heterostructures
made of 3-D semiconductors,” said Xu, who has joint appointments in the
Department of Physics and the Department of Materials Science and Engineering.
“We’ve created a system to study the special properties of these atomically
thin layers and their potential to answer basic questions about physics and
develop new electronic and photonic technologies.”
When semiconductors absorb light, pairs of positive and
negative charges can form and bind together to create so-called excitons.
Scientists have long studied how these excitons behave, but when they are
squeezed down to the 2-D limit in these atomically thin materials, surprising
interactions can occur.