February 12, 2016

UW scientists create ultrathin semiconductor heterostructures for new technological applications


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.

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