A simple 230 MHz photodetector based on exfoliated WSe2 multilayers
Fabian Strauß1,2, Pia Kohlschreiber1,2, Jakob Keck1,2
1Institute for Physical and Theoretical Chemistry, University of Tübingen 72076 Tübingen Germany marcus.scheele@uni-tuebingen.de.
RSC Applied Interfaces
|July 11, 2024
Summary
We achieved 230 MHz photodetection using tungsten diselenide (WSe2) multilayers, significantly improving speed and reducing energy consumption. This breakthrough enables ultrafast and efficient optical sensing with atomically thin materials.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Optoelectronics
Background:
- Transition metal dichalcogenides (TMDs) like WSe2 are promising for optoelectronic applications.
- Previous WSe2 photodetectors exhibited slower response times compared to their potential.
- Understanding the factors limiting photodetection speed in TMDs is crucial for device advancement.
Purpose of the Study:
- To demonstrate high-speed photodetection using WSe2 multilayers.
- To investigate methods for reducing the RC constant in WSe2 photodetectors.
- To explore the feasibility of ultrafast photodetection in atomically thin WSe2.
Main Methods:
- Fabrication of WSe2 multilayer photodetectors with a simple device architecture.
- Systematic reduction of the device RC constant by decreasing photoresistance and capacitance.
- Characterization of photodetection performance, including frequency response and switching energy.
Main Results:
- Achieved photodetection at 230 MHz with a switching energy of 27 fJ.
- Demonstrated that reducing WSe2 thickness to the monolayer limit minimally impacts response time.
- Showcased significant improvements over previous, slower WSe2 photodetector designs.
Conclusions:
- Ultrafast photodetection is achievable with WSe2, even in atomically thin forms.
- Optimizing the RC constant is key to enhancing the speed of WSe2 photodetectors.
- Gigahertz photodetection using pure TMDs is a feasible future direction.
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