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Vibronic Exciton-Phonon States in Stack-Engineered van der Waals Heterojunction Photodiodes
Fatemeh Barati, Trevor B Arp, Shanshan Su
1Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
Nano Letters
|July 5, 2022
Summary
Stack engineering in van der Waals heterostructures reveals strong coupling between atomic motion and interlayer excitons. This study demonstrates tunable vibronic states in WSe2/MoSe2 photodiodes using photocurrent spectroscopy.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Stack engineering is a key strategy for designing optical and electronic properties in van der Waals heterostructures.
- Interlayer excitons in 2D material heterojunctions are crucial for optoelectronic applications.
Purpose of the Study:
- To investigate the optoelectronic effects of stacking-induced strong coupling between atomic motion and interlayer excitons.
- To demonstrate the utility of photocurrent spectroscopy for probing vibronic states in heterojunction photodiodes.
Main Methods:
- Fabrication of stack-engineered WSe2/MoSe2 heterojunction photodiodes.
- Utilizing photocurrent spectroscopy to probe interlayer excitons and their vibronic states.
- Applying perpendicular electric fields via source-drain bias to tune spectral features.
Main Results:
- Observation of pronounced, periodic sidebands in photocurrent spectra near interlayer exciton resonances.
- Demonstration of tunable vibronic states through applied electric fields.
- Evidence for the emergence of interlayer exciton vibronic structure in optoelectronic devices.
Conclusions:
- Stack engineering enables strong coupling between atomic motion and interlayer excitons.
- Photocurrent spectroscopy is a sensitive method for accessing vibronic states in 2D heterostructures.
- Tunable vibronic structure in WSe2/MoSe2 photodiodes opens new avenues for optoelectronic device design.
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