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Ultrabroadband and polarization‐sensitive imaging are essential for pioneering advancements in intelligent technology, offering a pivotal pathway to multidimensional information extraction. However, the dearth of appropriate photosensitive semiconductors in the infrared region and the lack of suitably efficient device architecture for the separation and collection of photocarriers significantly impede the development of ultra‐broadband and polarization‐sensitive photodetectors. To address these challenges, a sandwiched Ta2NiSe5/MoTe2/Graphene heterostructure device is engineered. In this device, efficient and polarization‐sensitive photocarriers are generated in the top Ta2NiSe5 layer, rapidly separated through the middle MoTe2 layer, and effectively collected by the bottom graphene layer. As a result, the developed photodetector exhibits an ultra‐broadband and polarization‐sensitive photoresponse that extends from visible light (520 nm) to short‐wave infrared (2200 nm). At 2200 nm, the device displays a notable responsivity of 5.79 A W−1, a specific detectivity of 1010 Jones, and an anisotropic ratio of 1.44. Furthermore, this device successfully demonstrates high‐resolution ultra‐broadband and polarized light imaging capabilities. This study thus presents an intriguing blueprint for the development of advanced 2D imaging platforms for future‐generation intelligent systems. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) self‐powered photodetectors have attracted considerable attention due to their exceptional sensitivity, and low dark current. However, the poor responsivity of single heterojunctions with type‐III band alignment is primarily attributed to band‐to‐band tunneling. The implementation of a double heterojunction has the potential to enhance photovoltaic responsivity, enable broadband detection, and improve response speed. In this study, a back‐to‐back type‐III band alignment based on SnSe2/Bi2Se3/MoTe2 double heterostructure by dry transfer method is designed. As a result, it exhibited an impressive photovoltaic performance in the overlapping region. Achieving a maximum responsivity (R), external quantum efficiency (EQE), photoelectric conversion efficiency (PCE), and specific detectiviy (D*) of 493 mA W−1, 76 %, 3 % and 1.8 × 1011 Jones at a gate voltage (Vg) of 60 V under 808 nm illumination. It can be ascribed to the effective depletion region at the SnSe2/Bi2Se3 interface and the reversed band edge from depletion to accumulation mode at Bi2Se3/MoTe2 interface. In addition, a faster response speed of 553/583 µs and a lower dark current of 2.9 pA can be obtained. Moreover, this double heterostructure achieves better photovoltaic performance with Vg compared to the single MoTe2/SnSe2 heterojunction. These results demonstrates the potential as a candidate for back‐to‐back type‐III band alignment in low power optoelectronics. [ABSTRACT FROM AUTHOR]

2D p–n homojunctions exhibit distinctive structural properties, including continuous energy band structure and perfect lattice matching, making them promising for the design of optoelectronic and electronic devices. Herein, we present a straightforward approach to fabricate a highly sensitive, self-driven photodetector based on a WS2 homojunction. The p-doping on the WS2 interface is easily achieved through water treatment, eliminating the need for chemical dopants. There is an evident reversal of polarity in the WS2 devices treated as compared to the intrinsic WS2. Particularly, the mobility of the weak p-doping WS2 field-effect transistor is 0.65 cm2 V−1 s−1, and the on/off ratio can reach 103 after water treatment. The WS2 p–n homojunction can be prepared by local boron nitride covering on n-type WS2. Moreover, the lateral p–n homojunction demonstrates remarkable photovoltaic properties, including a maximum short-circuit current of 7.55 nA and an open-circuit voltage of 0.15 V. Additionally, due to the effective in-plane built-in field, the device achieves a high Ilight/Idark ratio of nearly 105, a high specific detectivity of 5.8 × 1011 Jones, and a large linear dynamic range of 60 dB. This investigation offers a promising facile and soft avenue for the design of high-performance self-driven homojunction photodetectors with potential applications in low-consumption optoelectronics. [ABSTRACT FROM AUTHOR]

With the rapid development of two‐dimensional semiconductor technology, the inevitable chemical disorder at a typical metal–semiconductor interface has become an increasingly serious problem that degrades the performance of 2D semiconductor optoelectronic devices. Herein, defect‐free van der Waals contacts have been achieved by utilizing topological Bi2Se3 as the electrodes. Such clean and atomically sharp contacts avoid the consumption of photogenerated carriers at the interface, enabling a markedly boosted sensitivity as compared to counterpart devices with directly deposited metal electrodes. Typically, the device with 2D WSe2 channel realizes a high responsivity of 20.5 A W−1, an excellent detectivity of 2.18 × 1012 Jones, and a fast rise/decay time of 41.66/38.81 ms. Furthermore, high‐resolution visible‐light imaging capability of the WSe2 device is demonstrated, indicating its promising application prospect in future optoelectronic systems. More inspiringly, the topological electrodes are universally applicable to other 2D semiconductor channels, including WS2 and InSe, suggesting its broad applicability. These results open fascinating opportunities for the development of high‐performance electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

2D semiconductors are regarded as the potential channel materials for high‐performance integrated optoelectronics. However, the absence of an effective photoconductive gain mechanism and the adverse effects from traditional SiO2 substrate prevent the further breakthrough of the photosensitivity of 2D semiconductors‐based photodetectors. Here, an ingenious out‐of‐plane heterostructure is proposed for boosting the photosensitivity. Sub‐millimeter scale (>700 µm) tri‐layer WSe2 with high quality and uniformity is robustly deposited and integrated with 2D photosensitive channels for gate‐tunable photodetection. The WSe2 with naturally passivated surface can not only serve as a substrate passivation layer to mitigate the detrimental substrate effects, but also introduces vertical built‐in fields, which efficiently separates the photogenerated carriers and produces high photoconductive gain. Under gate voltage modulation, the proposed InSe photodetector exhibits a series of excellent performances, including responsivity of 112 A W−1, detectivity of 8.6 × 1012 Jones, light on/off ratio of 1.3 × 104 and rise/decay time of 29.1/15.3 ms. More inspiringly, this heterostructure scheme is universally applicable to 2D WS2 photodetector and also significantly improves its photosensitivity, demonstrating broad applicability. This research will provide helpful guidance for the design and optimization of customizable optoelectronic devices based on 2D semiconductors. [ABSTRACT FROM AUTHOR]

Ultrasensitive photodetectors with high responsivity, detectivity, and fast response rate have triggered urgent demand in extensive applications. In recent years, 2D indium chalcogenides have emerged as appealing photoactive materials due to their excellent electrical and optoelectronic properties. However, suffering from the weak optical absorption induced by atomically thin thickness as well as the short lifetime of photogenerated carriers, conventional 2D indium chalcogenides photodetectors commonly exhibit limited photodetection performance. Herein, a universal strategy integrating 2D indium chalcogenides and Si nanostripe array is demonstrated. The Si nanostripes afford Mie‐type resonance, which facilitates light absorption. In addition, the introduction of photoconductive gain and strain engineering prolongs photogenerated carriers' lifetime and accelerates their transport. The coupling effect of these three mechanisms enables the device to exhibit high photodetection performance. The constructed α‐In2Se3 device manifests a high responsivity of 9.4 × 103 A W−1, detectivity of 5.5 × 1013 Jones while maintaining fast rise/decay time of 2.7/3.8 ms. In addition, this proposed strategy can also be employed to construct InSe device with comprehensively enhanced photodetection performance, which presents universality and wide applicability. These results demonstrate that advanced device design is an effective avenue to achieve future multifunctional optoelectronic devices with high sensitivity. [ABSTRACT FROM AUTHOR]

2D indium chalcogenides including α‐In2Se3 and InSe are promising candidates for next‐generation optoelectronic devices. However, the performance of traditional SiO2‐supported devices is limited because of the detrimental effect of the substrate, which greatly restricts charge transportation. Although the induction of an internal (built‐in) electric field can alleviate this situation, the application of conventional stacking technology required in this case inevitably introduces interface defects. Against this backdrop, in this study, a simple and universal structure for the fabrication of highly sensitive photodetectors is designed and engineered. A SiO2 window to afford a "suspended" α‐In2Se3 channel, effectively eliminating the detrimental effects of the substrate, is etched. In addition, the approach induces local strain in the suspended α‐In2Se3, which regulates the band structure and introduces intramolecular type‐II alignment. Thus, the interfacial charge transfer is optimized, and the photodetection performance is enhanced. The resulting device exhibits excellent photosensitivity (responsivity of 1672 A W−1, on/off ratio of 263, and detectivity of 7.5 × 1013 Jones), and a relatively fast response rate (12 ms for both rise and decay). This structure can also be extended to InSe devices to comprehensively enhance their photodetection performance, thereby demonstrating the broad applicability of the proposed method. [ABSTRACT FROM AUTHOR]

Two‐dimensional‐material‐based self‐driven photodetectors show high sensitivity, fast and broadband response under built‐in electric field in a P–N junction configuration. However, the methods, including doping and multiple transfer processes, for constructing the heterostructures is complex and time‐costing. On the other hand, asymmetric Schottky barrier heights caused by metal electrodes scale, kinds, contact area and thickness can lead to zero‐bias driven photo‐response. In this work, a metal–semiconductor–metal irregular WS2 photodetector with symmetric electrodes are achieved by wet‐transfer. A high zero‐bias photo‐responsivity of 777 mA W−1, a fast response speed of 7.8/37.2 ms, a Ilight/Idark ratio of 104 and a high detectivity of 4.94 × 1011 Jones under 405 nm light are obtained because of a Schottky barrier height difference of ≈50.2 mV through Fermi‐level pinning effect and different contact area. The responsivity at −2 V is stable in the range of 2.23 to 3.45 A W−1 and the empirical factor reaches to 0.99 by the efficient carrier generation process. The WS2 asymmetric Schottky photodetectors outperform most heterostructure based photodiodes. This paper provides a facile route toward self‐powered photodetectors with high performance, easy processing and simple architecture for future applications. [ABSTRACT FROM AUTHOR]