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Flexo-Pyrophotronic Effect Modulated Giant Near Infrared Photoresponse from VO2 -Based Heterojunction for Optical
Mohit Kumar1,2, Dukhwan Kim1, Hyungtak Seo1,2
1Department of Energy Systems Research, Ajou University, Suwon, 16499, Republic of Korea.
Small Methods
|July 9, 2023
Summary
This study demonstrates a self-powered infrared sensor using flexoelectricity in VO2 heterojunctions. The device offers sensitive and rapid detection, enabling applications like night vision and obstacle sensing.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Flexoelectricity generates electric polarization from strain gradients in materials.
- Mechano-optoelectronics offer energy-saving applications but require sensitive, self-powered sensors.
- Challenges exist in achieving stable photocurrent and fast response for weak signal detection.
Purpose of the Study:
- To investigate the flexoelectric phenomenon in VO2-based heterojunctions for self-powered infrared sensing.
- To develop a device capable of detecting weak infrared signals with high sensitivity and rapid response.
- To demonstrate proof-of-concept applications in optical communication and sensing.
Main Methods:
- Fabrication of a centrosymmetric VO2-based heterojunction.
- Utilizing flexoelectric effects to induce a photoresponse under infrared light (940 nm).
- Applying inhomogeneous mechanical force to modulate and enhance the infrared response sensitivity.
Main Results:
- The VO2 heterojunction exhibited a self-powered (0 V) infrared photoresponse.
- Achieved giant current modulation (>1000%), responsivity (>2.4 mA W⁻¹), detectivity (≈10¹⁰ Jones), and fast response speed (0.5 ms).
- Enhanced infrared response sensitivity by over 640% through force manipulation.
Conclusions:
- Flexoelectricity in VO2 heterojunctions enables efficient self-powered infrared sensing.
- The developed device shows potential for ultrafast optical communication and high-performance obstacle sensors.
- Mechanoelectrical coupling offers a promising avenue for novel optoelectronic devices and systems.
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