Qianjin Wang

A dual‐band device that can simultaneously possess high sensitivity and neuron‐like processing capabilities is highly desirable for next‐generation intelligent optoelectronic systems. However, traditional single‐material devices have the problems of poor performance and low integration level. Furthermore, due to their high‐power consumption, they are limited in applications such as integrated sensing, computing and storage, optical encryption communication, and imaging. Here, we report a multifunctional CuInP ₂ S ₆ (CIPS)/Ga ₂ O ₃ heterojunction that integrates ultraviolet (UV–Visible photodetection, artificial synaptic function, neuron‐like recognition, and dual‐wavelength optical communication and imaging. Notably, this constructed type‐II CIPS/Ga ₂ O ₃ van der Waals heterojunction provides an opportunity to modulate the interface charge carrier transport, then enhance the light absorbance, thereby achieving high responsivity (275 A/W), and enhanced detectivity (1.95 × 10 ¹⁵ Jones) under irradiation of 245 nm UV light. Significantly, the device also exhibits vital synaptic plasticity, including dual‐pulse promotion and adjustable memory retention capability. By mapping the experimentally extracted single‐device forgetting dynamics to a simulated convolutional neural network framework, high accuracy has been achieved on both simple and complex datasets. Additionally, wavelength‐selective light response supports dual‐band UV‐visible light communication and imaging. This work establishes a multifunctional heterojunction platform, advancing the research and development of modern optoelectronics.

High‐performance photodetectors for low‐light imaging and high‐speed information processing require high responsivity, high specific detectivity, fast response, and ultralow power consumption enabled by minimal dark current. Although 2D van der Waals heterojunctions can suppress dark current and promote carrier separation via built‐in electric fields, most reported devices still rely on external bias, limiting their application in energy‐efficient integrated systems. Moreover, integrating self‐powered photodetection with programmable optoelectronic logic in a single device remains challenging. Here, we report a vertical trilayer vdW heterojunction phototransistor based on PdSe ₂ /SnS ₂ /MoS ₂ with synergistic functionality. By strengthening the built‐in electric field and optimizing interfacial energy‐level alignment, this architecture suppresses the dark current to the picoampere level while bringing the ideality factor close to unity (η ≈ 1). The device operates in a fully self‐powered mode, achieving a high responsivity of 654 mA W ⁻¹ and a specific detectivity of 5.4 × 10 ¹² Jones under 638 nm illumination—surpassing most previously reported PdSe ₂ ‐based self‐powered photodetectors. Beyond photodetection, gate‐voltage modulation enables switchable multistable output states, thereby seamlessly integrating self‐powered sensing with programmable optoelectronic logic in a single device. This work establishes a viable device paradigm for low‐power, highly integrable visible and near‐infrared optoelectronic logic systems.

Ferroelectric phototransistors have emerged as promising platforms for integrating sensing, memory, and computing toward artificial intelligence systems, however, their practical applications are hindered by limited photoresponse and insufficient device performance. Here, we report a high-performance CuInP2S6 (CIPS)/CdS0.42Se0.58 ferroelectric heterojunction transistor enabled by a dry-transfer strategy, which synergistically combines ferroelectric polarization modulation with band-engineered heterointerfaces. The device exhibits outstanding optoelectronic performance, including a high light-to-dark current ratio of 4.37×105, a responsivity of 5.38×103 A/W, an external quantum efficiency of 1.14×106%, and a specific detectivity up to 3.67×1015 Jones, along with a fast response time of 78/320 μs. Importantly, polarization switching effectively tunes carrier transport by modulating the depletion region at the heterointerface, enabling controllable photoresponse characteristics. Leveraging these advantages, the device is further demonstrated for visible-light imaging and convolutional neural network (CNN)-assisted image recognition, achieving an accuracy of 96.09%. Compared with previously reported CIPS-based devices, this work realizes a substantial improvement in both sensitivity and speed. This study highlights the effectiveness of ferroelectric-semiconductor heterostructure engineering for high-performance photodetection and provides a viable pathway toward highly integrated and intelligent optoelectronic systems.

Two-dimensional (2D) van der Waals heterojunctions have emerged as promising platforms for next-generation optoelectronic applications. Nevertheless, the concurrent realization of high photoresponsivity and rapid response speed within a single device remains a critical challenge, thereby limiting their practical implementation in low-power photodetection and polarization-resolved imaging. Herein, a novel symmetric SnSe2/ReS2/SnSe2 van der Waals heterojunction was fabricated via a dry-transfer technique, and a high-performance, low-power photodetector with polarization sensitivity was subsequently constructed. The superior optoelectronic performance of the device is primarily attributed to the formation of type-II band alignment at both heterointerfaces, which effectively promotes the spatial separation of photogenerated electron-hole pairs and suppresses carrier recombination. As a result, under 638 nm illumination at zero bias, the as-fabricated device exhibits outstanding self-powered photodetection characteristics, including a high responsivity of 56.03 mA W-1, a specific detectivity of 8.58×1012 Jones, and a fast response time of 67.5/59.3 μs. Notably, the device demonstrates a pronounced polarization-sensitive photoresponse, with an anisotropic photocurrent ratio (Imax/Imin) of 1.09 under the same conditions. This polarization-dependent behavior enables high-fidelity imaging across varying polarization angles. This study provides valuable insights into the design and optimization of high-performance, polarization-sensitive photodetectors based on 2D van der Waals heterostructures.

Based on the excellent physical properties of the two-dimensional materials InSe and ZrSSe, exploring whether their heterostructures can realize tunable band alignment has become an important scientific issue in the research of optoelectronic functional materials. In this work, first-principles calculations based on density functional theory (DFT) were employed to systematically investigate the evolution of the electronic structure and optical properties of InSe/ZrSSe van der Waals heterostructures (vdW heterostructures) under varying interlayer distances, strain, and external electric fields. The results show that both the InSe/SeZrS and InSe/SZrSe heterostructures exhibit type-II band alignment, enabling efficient interfacial separation of photoinduced electron–hole pairs and delivering excellent optical absorption from the visible to the near-infrared region. Notably, for the InSe/SZrSe heterostructure, both the conduction-band minimum (CBM) and valence-band maximum (VBM) shift regularly under either uniaxial or biaxial strain, when the strain exceeds 3%, the band alignment can transform from type II to type I. Moreover, under an applied out-of-plane electric field, heterostructure model can undergo transitions from type II to type I or even type III band alignment. These findings highlight the broad application potential of InSe/ZrSSe heterostructures in photocatalysis and optoelectronic devices, and provide a solid theoretical basis for their experimental fabrication and device design.

Photodetectors with high sensitivity and polarization selectivity are critical for applications ranging from environmental monitoring to advanced imaging. Transition metal dichalcogenides (TMDs) offer remarkable stability, yet their low photocurrent-to-dark current ratio and intrinsic limitations hinder their exploration in polarization-resolved visible light imaging and nonlinear optics. Here, we present a MoTe2/CdS/ReS2 dual heterojunction photodetector exhibiting outstanding performance and nonlinear optical response. The device achieves a responsivity of 492.7 A/W, an on/off current ratio of 4.15 × 106, rapid response times of 172/299 μs, an external quantum efficiency up to 1.04 × 105%, and a detectivity of 3.12 × 1015 Jones. It displays pronounced polarization-dependent photocurrent and enables high-fidelity imaging under varying polarization angles. Second harmonic generation mapping confirms strong second-order nonlinear optical activity arising from inversion symmetry breaking, while photoluminescence mapping reveals efficient interlayer charge separation. Band structure analysis elucidates the mechanisms underpinning the enhanced photoresponse. This work establishes a platform for nonlinear optical polarized imaging and offers a pathway to advance the optoelectronic performance of TMD-based materials.

Photodetectors based on Bi₂O₂Se currently suffer from low responsivity, limited detection sensitivity, and insufficient broadband photoresponse capability, which significantly hinders their practical application in high-performance optoelectronic devices. To overcome these limitations, this study designs and fabricates a broadband (300–1300 nm), high-performance photodetector based on a vertically stacked Bi₂O₂Se/CdSe heterojunction. Under 560 nm illumination and a 5 V bias voltage, the device exhibits a high responsivity of 6.18×10³ A/W, an on/off ratio of 1.46×10⁴, and a specific detectivity of 1.95×10¹⁴ Jones. Remarkably, even under zero-bias conditions, the device maintains a responsivity of up to 1.99 A/W, a detectivity of 6.23×10¹⁰ Jones, and an on/off ratio of 2.52×10³, demonstrating outstanding self-powered characteristics. This work not only proposes an efficient strategy for constructing high-performance heterojunction that effectively break through the limitations of conventional photodetectors, but also elucidates the critical role of interfacial engineering in enhancing the self-driven behavior of the device, thereby providing a theoretical foundation and technical support for the development of low-power, high-performance photodetection systems.