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Updated: Jun 17, 2025
13:56
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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Composition Modulation-Mediated Band Alignment Engineering from Type I to Type III in 2D vdW Heterostructures
Dingli Guo1,2, Qiang Fu1, Guitao Zhang1
1School of Physics and Key Laboratory of Quantum Materials and Devices of Ministry of Education, Southeast University, Nanjing, 211189, China.
Advanced Materials (Deerfield Beach, Fla.)
|August 10, 2024
Summary
Band alignment engineering in WSe2/Bi2Te3-xSex van der Waals heterostructures (vdWHs) was tuned from Type I to Type III. This tuning impacts photodetector performance and enhances light-emitting diode (LED) efficiency.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Band alignment engineering is critical for optimizing charge dynamics in optoelectronic devices like photodetectors and light-emitting diodes (LEDs).
- The influence of band offsets in van der Waals heterostructures (vdWHs) on device performance metrics remains underexplored.
- WSe2/Bi2Te3-xSex vdWHs offer a tunable platform for investigating band alignment effects.
Purpose of the Study:
- To systematically investigate the impact of tunable band alignment on the performance of WSe2/Bi2Te3-xSex vdWHs.
- To correlate changes in band alignment (Type I to Type III) with optoelectronic device characteristics.
- To demonstrate the potential of engineered band alignment for advanced photodetectors and LEDs.
Main Methods:
- Chemical vapor deposition (CVD) was employed to synthesize WSe2/Bi2Te3-xSex vdWHs with varying compositions (0 ≤ x ≤ 3).
- A combination of experimental characterization and theoretical calculations was used to determine band alignment.
- Fabrication and testing of vdWH-based photodetectors and LEDs were performed to evaluate device performance.
Main Results:
- The band alignment of WSe2/Bi2Te3-xSex vdWHs was successfully tuned from Type I (WSe2/Bi2Te3) to Type III (WSe2/Bi2Se3).
- Photodetectors based on Type I vdWHs exhibited high responsivity (58.12 A/W) and detectivity (2.91×10^12 Jones), while Type III vdWHs showed ultrafast photoresponse (3.2 µs).
- Type III vdWH-based LEDs demonstrated superior luminance and electroluminescence external quantum efficiencies (EQE) compared to other Transition Metal Dichalcogenide (TMD) p-n diodes at room temperature.
Conclusions:
- Tunable band alignment in WSe2/Bi2Te3-xSex vdWHs significantly influences optoelectronic device performance.
- The transition from Type I to Type III band alignment offers distinct advantages for photodetectors and LEDs.
- Engineered band alignment is a promising strategy for designing high-performance optoelectronic devices based on vdWHs.
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