Tuning ultrafast electron thermalization pathways in a van der Waals heterostructure
By Q. Ma, T. Andersen, N. Nair, N. Gabor, M. Massicotte, C. Lui, A. Young, W. Fang, Kenji Watanabe, Takashi Taniguchi and 4 more. Nature Physics, 2016
155 citations recorded by the source corpus.
Interlayer transport can be made to occur slower or faster than intralayer scattering in van der Waals heterostructures, allowing the thermalization pathways for optically excited carriers to be tuned. Ultrafast electron thermalization—the process leading to carrier multiplication via impact ionization1,2, and hot-carrier luminescence3,4—occurs when optically excited electrons in a material undergo rapid electron–electron scattering3,5,6,7 to redistribute excess energy and reach electronic thermal equilibrium. Owing to extremely short time and length scales, the measurement and manipulation of electron thermalization in nanoscale devices remains challenging even with the most advanced ultrafast laser techniques8,9,10,11,12,13,14. Here, we overcome this challenge by leveraging the atomic thinness of two-dimensional van der Waals (vdW) materials to introduce a highly tunable electron transfer pathway that directly competes with electron thermalization. We realize this scheme in a graphene–boron nitride–graphene (G–BN–G) vdW heterostructure15,16,17, through which optically excited carriers are transported from one graphene layer to the other. By applying an interlayer bias voltage or varying the excitation photon energy, interlayer carrier transport can be controlled to occur faster or slower than the intralayer scattering events, thus effectively tuning the electron thermalization pathways in graphene. Our findings, which demonstrate a means to probe and directly modulate electron energy transport in nanoscale materials, represent a step towards designing and implementing optoelectronic and energy-harvesting devices with tailored microscopic properties.
Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/383868fa6dd30e40f751b218f27816e1a3e95670
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Atomic and Molecular Physics, and Optics
Citations in the corpus
- Colloquium: Nonthermal pathways to ultrafast control in quantum materials (2021, background): “…dynamics have also been probed in carbon nanotubes (Gabor et al., 2012), graphene (Sun et al., 2012), and various van der Waals heterostructures (Ma et al., 2016; Massicotte et al., 2016; Arp et al., 2019) by measuring the photocurrent generated in response to two time-delayed laser pulses.”