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Probe Type II Band Alignment in One-Dimensional Van Der Waals Heterostructures Using First-Principles Calculations
Published on: October 12, 2019
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Ferroelectric-tuned van der Waals heterojunction with band alignment evolution.
Yan Chen1,2, Xudong Wang1, Le Huang3
1State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, China.
Nature Communications
|June 30, 2021
Summary
We developed a ferroelectric-tuned van der Waals heterojunction using GeSe/MoS2 and a ferroelectric polymer. This design enables tunable band alignment for high-performance, polarization-sensitive photodetectors.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Van der Waals heterojunctions are key for advanced functional devices.
- Band alignment engineering is critical for optimizing heterojunction performance.
- Two-dimensional materials offer versatile platforms for novel electronic and optoelectronic applications.
Purpose of the Study:
- To design and demonstrate a ferroelectric-tuned van der Waals heterojunction for enhanced optoelectronic properties.
- To investigate the modulation of band alignment in GeSe/MoS2 heterojunctions using ferroelectric polarization.
- To develop a high-performance polarization-sensitive photodetector with improved characteristics.
Main Methods:
- Fabrication of a van der Waals heterojunction by integrating GeSe/MoS2 with a ferroelectric polymer (polyvinylidene fluoride-trifluoroethylene).
- Application of an ultrahigh electric field from ferroelectric polarization to tune band alignment.
- Characterization of the heterojunction's optoelectronic properties, including current-voltage measurements and photoresponse analysis.
Main Results:
- Demonstrated a transition of band alignment from type II to type I in the GeSe/MoS2 heterojunction.
- Achieved a high-performance polarization-sensitive photodetector with a low dark current (~1.5 pA), fast response time (14 μs), and high detectivity (4.7 × 10^12 Jones).
- Observed enhanced dichroism ratios across a broad spectrum (visible to near-infrared) due to ferroelectric tuning.
Conclusions:
- The ferroelectric-tuned GeSe/MoS2 van der Waals heterojunction shows significant potential for multifunctional light information sensing.
- Ferroelectric polarization offers an effective method for band engineering in van der Waals heterojunctions.
- This approach provides a versatile strategy for creating advanced optoelectronic devices.
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