Key Takeaways & Executive Findings
- •• • The Te/Bi2O2Se heterojunction photodetector achieves a responsivity of ~0.89 A·W−1 under 1550 nm irradiation in self-powered mode, enabling efficient detection without external bias, which is critical for low-power infrared sensing systems. • • The device exhibits a fast response time of ~29/41 μs (rise/fall), facilitating high-speed optical communication and imaging applications where rapid signal acquisition is essential. • • A high polarization ratio of 2.8 is achieved due to the intrinsic optical anisotropy of tellurium, allowing polarization-sensitive detection for applications such as ellipsometry, remote sensing, and secure optical communications. • • The heterojunction is fabricated via a two-step chemical vapor deposition method, ensuring a clean interface and type-II band alignment, which is essential for efficient charge separation and high detectivity in mixed-dimensional vdW heterostructures.
Abstract
Low-dimensional semiconductors have attracted widespread attention in next-generation broadband infrared photodetectors due to their tunable band structures, strong light-matter interactions, and compatibility with mixed-dimensional integration. Among them, tellurium (Te) and bismuth selenide (Bi2O2Se) are ideal candidates for high-performance detection owing to their inherent anisotropy, high carrier mobility, and broad spectral response. Constructing heterojunction photodetectors based on these materials enables self-powered operation and suppresses dark current. Heterojunction interface engineering and band structure design are crucial for high-performance Te/Bi2O2Se heterojunction photodetectors. Here, we in-situ construct a one-dimensional (1D) Te/two-dimensional (2D) Bi2O2Se heterojunction via a two-step chemical vapor deposition method, achieving a clear interface and type-II band alignment. The photodetector based on the Te/Bi2O2Se heterojunction, operating in self-driven mode, exhibits high performance: a responsivity of ~0.89 A·W−1 and a fast response time of ~29/41 μs under 1550 nm light irradiation. Furthermore, owing to the optical absorption anisotropy of tellurium, the device demonstrates a high polarization ratio of 2.8 and successfully enables polarization optical communication and polarization imaging applications. This work provides new insights into the in-situ construction strategy for high-quality mixed-dimensional van der Waals heterojunctions and advances high-performance photodetectors and their applications.
1. Introduction
Conventional infrared photodetectors based on bulk semiconductors face fundamental limitations: lattice mismatch and covalent bonding constraints hinder heterojunction integration, while high dark currents and slow response times degrade performance. Low-dimensional van der Waals (vdW) materials offer atomic-level thickness, tunable bandgaps, and strong light-matter interactions, but constructing high-quality heterojunctions with controlled interfaces remains challenging. The lack of scalable, in-situ fabrication methods for mixed-dimensional vdW heterostructures has impeded their practical deployment in high-speed, self-powered photodetection.
This work addresses these bottlenecks by demonstrating an in-situ growth strategy for 1D Te/2D Bi2O2Se heterojunctions via two-step chemical vapor deposition. The resulting type-II band alignment and clean interface enable self-powered operation with suppressed dark current, achieving a responsivity of 0.89 A·W−1 and response times of 29/41 μs at 1550 nm. Furthermore, the inherent anisotropy of Te yields a polarization ratio of 2.8, enabling polarization-sensitive detection. This approach provides a scalable route to high-performance, multifunctional infrared photodetectors, overcoming prior limitations in heterojunction fabrication and device performance.
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Xingbo Shang, Maohua Chen, Yiye Yu, Tiange Zhao, Yuzhuo Bai, Shikun Duan, Haonan Ge, Zhen Wang, Longhui Zeng, Di Wu (2026). In-situ grown 1D Te/2D Bi2O2Se van der Waals heterostructure for high-performance self-powered polarization-sensitive photodetection. SinoTechIntel Verified Research. https://doi.org/10.26599/NR.2026.94908666
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Frequently Asked Questions
What is the long-term operational stability of the Te/Bi2O2Se heterojunction photodetector under continuous illumination and ambient conditions?
The paper does not provide explicit long-term stability data. However, Te is noted for high environmental stability, and the device is fabricated via CVD, which typically yields robust interfaces. Further stress testing under continuous 1550 nm illumination and varying humidity would be required to quantify degradation rates.
How does the device performance compare with state-of-the-art commercial InGaAs photodetectors in terms of specific detectivity and noise equivalent power?
The paper reports responsivity and response time but does not provide specific detectivity or noise equivalent power values. The self-powered operation and low dark current suggest competitive performance, but direct comparison requires additional measurements under identical conditions.
What is the scalability of the two-step CVD method for wafer-scale production, and what are the main bottlenecks?
The two-step CVD method is inherently scalable to large-area substrates, but uniformity of Te nanowire growth and precise alignment with Bi2O2Se nanosheets remain challenges. The paper demonstrates feasibility on a laboratory scale; industrial scale-up would require optimization of growth parameters and transfer processes.
What is the polarization extinction ratio at different wavelengths, and how does it vary with incident angle?
The paper reports a polarization ratio of 2.8 under 1550 nm illumination. Detailed wavelength-dependent and angle-dependent polarization performance is not provided, but the anisotropy of Te suggests wavelength dependence. Further characterization across the spectral range would be necessary.
What is the device yield and reproducibility of the heterojunction fabrication process?
The paper does not specify yield or reproducibility statistics. The in-situ growth method appears reliable, but quantitative data on device-to-device variation would be essential for manufacturing viability.
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