optoelectronics tagged posts

Image of one of the graphene-based devices Xu and colleagues worked with. Credit: Lei Wang

In traditional light-harvesting methods, energy from 1 photon only excites 1 electron or none depending on the absorber’s energy gap. The remaining energy is lost as heat. But a new article describe an approach to coax photons into stimulating multiple electrons. Their method exploits some surprising quantum-level interactions to give one photon multiple potential electron partners.

Wu and Xu in UW’s Dept of Materials Science & Engineering and the Det of Physics, made this surprising discovery using graphene.
The researchers took a single atom layer of graphene and sandwiched it between 2 thin layers of boron-nitride. Electrons do not flow easily within boron-nitride so it is an insulator.

When the g...

Berkeley Lab researchers have experimentally confirmed strong in-plane anisotropy in thermal conductivity along the zigzag (ZZ) and armchair (AC) directions of single-crystal black phosphorous nanoribbons. Credit: Junqiao Wu, Berkeley Lab

Researchers have confirmed single-crystal black phosphorous nanoribbons display a strong in-plane anisotropy in thermal conductivity, up to a factor of 2, along the zigzag and armchair directions of single-crystal black phosphorus nanoribbons. An experimental revelation that should facilitate the future application of this highly promising material to electronic, optoelectronic and thermoelectric devices.

“Imagine the lattice of black phosphorus as a 2D network of balls connected with springs, in which the network is softer along one direction of the plan...