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Dark exciton anti-funneling in atomically thin semiconductors
Roberto Rosati1, Robert Schmidt2, Samuel Brem1
1Department of Physics, Philipps-Universität Marburg, 35032, Marburg, Germany.
Nature Communications
|December 11, 2021
Summary
Atomically thin semiconductors use excitons, not electric fields, for transport. New research reveals excitons move away from strain, enabling novel control strategies for nanoelectronic devices.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanoscience
Background:
- Charge carrier transport is fundamental to nanoelectronics.
- Atomically thin semiconductors rely on excitons (neutral electron-hole pairs) for transport, which are not electrically controllable.
- Strain engineering offers a method to manipulate exciton propagation.
Purpose of the Study:
- To investigate exciton transport dynamics in atomically thin semiconductors under strain.
- To understand the influence of strain gradients on exciton movement.
- To explore novel methods for controlling exciton behavior in these materials.
Main Methods:
- Combined spatiotemporal photoluminescence measurements.
- Microscopic theoretical modeling.
- Tracking exciton behavior in time, space, and energy.
Main Results:
- Excitons exhibit anti-funneling behavior, moving away from high-strain regions.
- This phenomenon is attributed to the influence of dark excitons with opposing strain-induced energy variations.
- Demonstrated control over exciton transport through strain engineering.
Conclusions:
- Strain engineering can be used to control exciton transport in atomically thin semiconductors.
- The interplay between bright and dark excitons dictates strain-induced exciton movement.
- Findings pave the way for advanced applications in exciton-dominated nanoelectronics.
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