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High-sensitivity room-temperature multi-dimensional infrared (IR) detection is crucial for military and civilian purposes. Recently, the gapless electronic structures and unique optoelectrical properties have made the two-dimensional (2D) topological semimetals promising candidates for the realization of multifunctional optoelectronic devices. Here, we demonstrated the in-situ construction of high-performance 1T'-MoTe2/Ge Schottky junction device by inserting an ultrathin AlOx passivation layer. The good detection performance with an ultra-broadband detection wavelength range of up to 10.6 micron, an ultrafast response time of ~ 160 ns, and a large specific detectivity of over 109 Jones in mid-infrared (MIR) range surpasses that of most 2D materials-based IR sensors, approaching the performance of commercial IR photodiodes. The on-chip integrated device arrays with 64 functional detectors feature high-resolution imaging capability at room temperature. All these outstanding detection features have enabled the demonstration of position-sensitive detection applications. It demonstrates an exceptional position sensitivity of 14.9 mV/mm, an outstanding nonlinearity of 6.44%, and commendable trajectory tracking and optoelectronic demodulation capabilities. This study not only offers a promising route towards room-temperature MIR optoelectronic applications, but also demonstrates a great potential for application in optical sensing systems. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered materials have been considered promising candidates for next-generation optoelectronics. However, the performance of 2D photodetectors still has much room for improvement due to weak light absorption of planar 2D materials and lack of high-quality heterojunction preparation technology. Notably, 2D materials integrating with mature bulk semiconductors are a promising pathway to overcome this limitation and promote the practical application on optoelectronics. In this work, we present the patterned assembly of MoSe2/pyramid Si mixed-dimensional van der Waals (vdW) heterojunction arrays for broadband photodetection and imaging. Benefited from the light trapping effect induced enhanced optical absorption and high-quality vdW heterojunction, the photodetector demonstrates a wide spectral response range from 265 to 1550 nm, large responsivity up to 0.67 A·W−1, high specific detectivity of 1.84 × 1013 Jones, and ultrafast response time of 0.34/5.6 μs at 0 V. Moreover, the photodetector array exhibits outstanding broadband image sensing capability. This study offers a novel development route for high-performance and broadband photodetector array by MoSe2/pyramid Si mixed-dimensional heterojunction. [ABSTRACT FROM AUTHOR]

The 2D layered crystals can physically integrate with other non-2D components through van der Waals (vdW) interaction, forming mixed-dimensional heterostructures. As a new elemental 2D material, tellurium (Te) has attracted intense recent interest for high room-temperature mobility, excellent air-stability, and the easiness of scalable synthesis. To date, the Te is still in its research infancy, and optoelectronics with low-power consumption are less reported. Motivated by this, we report the fabrication of a mixed-dimensional vdW photodiode using 2D Te and 1D CdS nanobelt in this study. The heterojunction exhibits excellent self-powered photosensing performance and a broad response spectrum up to short-wave infrared. Under 520 nm wavelength, a high responsivity of 98 mA W−1 is obtained at zero bias with an external quantum efficiency of 23%. Accordingly, the photo-to-dark current ratio and specific detectivity reach 9.2 × 103 and 1.9 × 1011 Jones due to the suppressed dark current. This study demonstrates the promising applications of Te/CdS vdW heterostructure in high-performance photodetectors. Besides, such a mixed-dimensional integration strategy paves a new way for device design, thus expanding the research scope for 2D Te-based optoelectronics. [ABSTRACT FROM AUTHOR]

The stability and lead toxicity are two fundamental problems which might impede the application of halide perovskite photodetectors (PDs), and all-inorganic lead-free double halide perovskites might solve the problems simultaneously. Herein, we report that through constructing a p–i–n heterostructure based on a double halide perovskite, Cs2AgBiBr6, a self-powered ultraviolet-blue PD was prepared. With a low dark current of 1.89 × 10–9 A, the device showed a photoresponsivity of 33 mA/W, a specific detectivity of 3.28 × 1011 Jones, an on/off ratio of 1.16 × 103, and a response speed of 151/215 μs under illumination of 365 nm at zero bias. The device shows good thermal, humidity and oxygen stability. The results indicate that Cs2AgBiBr6 might be an ideal active material for developing high-performance short-wavelength PDs with extended spectral response range. [ABSTRACT FROM AUTHOR]

The research of ultraviolet photodetectors (UV PDs) have been attracting extensive attention, due to their important applications in many areas. In this study, PtSe2/GaN heterojunction is in-situ fabricated by synthesis of large-area vertically standing two-dimensional (2D) PtSe2 film on n-GaN substrate. The PtSe2/GaN heterojunction device demonstrates excellent photoresponse properties under illumination by deep UV light of 265 nm at zero bias voltage. Further analysis reveals that a high responsivity of 193 mA·W-1, an ultrahigh specific detectivity of 3.8 × 1014 Jones, linear dynamic range of 155 dB and current on/off ratio of ~ 108, as well as fast response speeds of 45/102 μs were obtained at zero bias voltage. Moreover, this device response quickly to the pulse laser of 266 nm with a rise time of 172 ns. Such high-performance PtSe2/GaN heterojunction UV PD demonstrated in this work is far superior to previously reported results, suggesting that it has great potential for deep UV detection. [ABSTRACT FROM AUTHOR]

The newly emerging copper halide Cs 3 Cu 2 I 5 is a promising candidate for deep-ultraviolet photodetector applications. However, the device performance available today is plagued by massive grain boundaries in Cs 3 Cu 2 I 5 polycrystalline films and unnecessary thicker volume in bulk single crystals. In this study, for the first time, highly crystalline and stable Cs 3 Cu 2 I 5 single-crystalline thin films (SCFs) were prepared by facile supersaturation-controlled growth strategy, with adjustable thickness ranging from 45 nm to 27.9 µm. By in situ monitoring the growth process, the crystallization kinetics of Cs 3 Cu 2 I 5 SCFs were elucidated, and the crystallization driving force comes from the slow inverse temperature nucleation and evaporation crystallization. Moreover, the substrate-independent growth feature of Cs 3 Cu 2 I 5 SCFs is intriguing for the direct on-chip fabrication of diverse photoelectric devices. The structural and electric characterizations reveal that the Cs 3 Cu 2 I 5 SCFs have a low trap density of 6.42 × 1011 cm−3, and the measured carrier lifetime and diffusion length are as long as 1.32 μs and 1.85 µm, respectively, which enable high deep-ultraviolet light detection capability of the proposed photoconductive detector based on Cs 3 Cu 2 I 5 SCFs. Encouraged by the robust operating stability of the fabricated device, the above results obtained could catalyze further research on on-chip manufacturing of deep-ultraviolet photodetectors. [Display omitted] • Cs 3 Cu 2 I 5 single-crystalline thin films were firstly demonstrated by a facile supersaturation-controlled growth. • We elucidated the crystallization kinetics of single-crystalline thin films based on classical nucleation theory. • The substrate-independent growth of single-crystalline films is intriguing for direct on-chip fabrication of diverse devices. • The single-crystalline thin films have lower trap density, larger carrier lifetime and longer diffusion length. • The photodetector demonstrates a good stability and a desired compatibility for practical applications. [ABSTRACT FROM AUTHOR]

Nitrogen-doped p-type ZnTe nanowires were successfully synthesized by a chemical vapor deposition method. Schottky junctions based on Au/ZnTe NW/In structure were constructed and their device performances were studied. ZnTe/In Schottky junction devices show excellent rectifying characteristics with rectification ratio up to 10 within ±5 V. Photoresponse analysis reveals that such devices were highly sensitive to varying optical signal with excellent stability, reproducibility and fast response speeds of 69/120 μs. These results demonstrate that ZnTe/In Schottky junction devices will promote the applications of ZnTe 1D nanostructures in electronic and optoelectronics. [ABSTRACT FROM AUTHOR]

Polarization‐sensitive solar‐blind ultraviolet (UV) photodetectors are essential in both civilian and military applications. 1D perovskites derivative Rb2CuCl3 holds promise for polarization‐sensitive solar‐blind UV photodetectors due to its wide direct bandgap, anisotropic crystal structure, and long carrier lifetime. However, no studies on the polarization properties of Rb2CuCl3 are reported. Here, the electronic structural anisotropy of Rb2CuCl3 is confirmed by calculating the partial charge density distribution in the ac‐plane and bc‐plane. Then, the Raman‐active modes and corresponding atomic vibration modes are explored within the bc‐plane through joint experimental and theoretical Raman spectroscopy. Besides, angle‐resolved Raman, photoluminescence, and absorption spectroscopy reveal the intriguing anisotropic photoelectric characteristics of Rb2CuCl3 microwires (MWs). By using single Rb2CuCl3 MW as the photoactive layer, a polarization‐sensitive solar‐blind UV photodetector is fabricated, showing high photoresponsivity of 78 mA W−1 and photocurrent anisotropy ratio of ≈1.7 at 265 nm. Importantly, the proposed photodetectors without encapsulation exhibit excellent stability in ambient air, retaining the original photocurrent after two months, showcasing practical applicability. This study underscores the promise of Rb2CuCl3 for high‐performance polarization‐sensitive solar‐blind UV photodetectors, contributing valuable insights into its electronic structure, photoelectric properties, and practical applicability. [ABSTRACT FROM AUTHOR]

Recently, the halide perovskites have increasingly received attention because of their superior capabilities in photodetector applications. However, the well‐known instability and lead‐toxicity are two major obstacles for their commercialization and practical applications. In this work, self‐powered photodetectors based on solution‐processed double perovskite Cs2AgBiBr6 films are fabricated for the first time. Owing to the high material integrity of Cs2AgBiBr6 and efficient interfacial charge transfer from perovskite to the underlying electron‐quenching layer, the photodetector demonstrates excellent performances. Especially, the unencapsulated device demonstrates a good working stability in the open air. Typically it has the ability to endure a high temperature of 373 K for 10 h continuous running, demonstrating a good temperature resistance. In addition, after 3‐month storage in open air, the photodetection capability of the device can almost be maintained. By deploying the photodetector as a point‐like sensing pixel, high‐resolution imaging patterns are acquired, which is the first report on imaging applications of lead‐free perovskite photodetectors. The obtained results suggest that the lead‐free double perovskite Cs2AgBiBr6 is potentially an attractive candidate to be applied in high‐efficiency and stable photodetectors that can be employed in optical imaging. [ABSTRACT FROM AUTHOR]

Abstract In this work, highly crystallized and lengths up to a centimeter organic-inorganic hybrid perovskite CH 3 NH 3 PbI 3 (MAPbI 3) microwires (MWs) have been prepared via a solution-based blade coating and slow solvent evaporation method. And a two-step growth mechanism was proposed to explain the formation and growth of the MAPbI 3 MWs. Further, the as-prepared MWs were used to fabricate photodetectors and their photoresponse characteristics were tested and detailedly analyzed. The results reveal that the devices presented stable and repeatable photocurrent responses. A high on/off photocurrent ratio of 0.84 × 104, a photoresponsivity of 0.04 A/W, a specific detectivity of 0.6 × 1012 Jones, and a fast response speed of 178/173 μs were realized in the prepared MAPbI 3 photodetectors. More importantly, even without encapsulation, the proposed photodetectors demonstrate remarkable operation stability, above 80% of the photocurrent has been retained after a long running time (50,000 s, 45–55% humidity). After 60 days storage without encapsulation in air ambient, the proposed photodetectors can be efficiently sustained, demonstrating a strong ability to resist the water and oxygen degradation, greatly superior to reference photodetectors constructed with MAPbI 3 thin films. This work opens up an exciting opportunity for using MAPbI 3 MWs for high-performance and low-cost photodetectors applications. Highlights • A solution-based blade coating and slow solvent evaporation method was used. • A two-step growth process was proposed to elucidate the growth mechanisms. • The devices have excellent on/off photocurrent ratio and response speed. • It shows remarkable operation stability and storage stability. [ABSTRACT FROM AUTHOR]

Photovoltaic MoS 2 /Si nanowire array (SiNWA) heterojunction photodetectors (PDs) are constructed and investigated, which exhibit excellent photoresponse properties to light illumination at wavelengths from the deep ultraviolet to the near-infrared. Further photoresponse analysis reveals that a high responsivity of 53.5 A/W and a specific detectivity of 2.8 × 10 13 Jones, as well as fast response speeds of 2.9/7.3 μs at 50 kHz are achieved in a MoS 2 /SiNWA heterojunction device. The high performances could be attributed to the high-quality heterojunction between MoS 2 and the SiNWA. Such high performances of MoS 2 /SiNWA PDs are much better than those of previously reported MoS 2 -based PDs, suggesting that MoS 2 /SiNWA heterojunction devices have great potential in optoelectronic applications. [ABSTRACT FROM AUTHOR]

High-quality ternary ZnS x Se 1-x nanowires (NWs) with tunable band-gaps were synthesized by a chemical vapor deposition (CVD) method. Photoluminescence (PL), absorption and Raman spectra were carried out to study their optical properties, revealing that the band-gaps of ZnS x Se 1-x NWs can be accurately controlled and cover the entire range from 2.65 eV to 3.7 eV by changing the component ratio. Optoelectronic properties were further studied by constructing photodetectors (PDs), which exhibited a high responsivity of 1.5 × 10 6 A W −1 , a photoconductive gain of 4.5 × 10 6 and fast response speed of 520/930 μs. Such high performances are superior to the previous reported results, indicating these ternary ZnS x Se 1-x nanostructures will have great potential applications in nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

• Cs 3 Cu 2 I 5 micro-wire arrays were prepared by microchannel-confined crystallization method. • The DUV detector exhibits a large responsivity of ∼ 23.6 A/W and a fast response speed of 2.9/370.7 μs. • Highly polarization-sensitive photodetection with a polarization sensitivity of 4.45 is achieved. • By deploying the detector as a sensing pixel, high-resolution polarized imaging patterns were acquired. Polarization-sensitive detectors operating in the deep-ultraviolet (DUV) region have been favored for their great meaning in the field of biological tissue morphology, image display systems and sensors. The advantages of intrinsic DUV light absorption, low-symmetry crystal structure and morphology anisotropy make Cs 3 Cu 2 I 5 micro-wire arrays the perfect choice for polarization-sensitive DUV photodetection. In this work, we demonstrate a polarization-sensitive DUV photodetector developed from the Cs 3 Cu 2 I 5 micro-wire arrays, which were prepared by a microchannel-confined crystallization strategy, and the optical and optoelectronic anisotropy of Cs 3 Cu 2 I 5 micro-wire arrays with adjustable sizes were systematically investigated. Owing to the high crystallinity and good carrier transportation ability of the Cs 3 Cu 2 I 5 micro-wires, the photodetector exhibits a large responsivity of ∼ 23.6 A/W and a fast response speed of 2.9/370.7 μs. Based on the intrinsic anisotropy of the asymmetric structure and external morphology anisotropy of the Cs 3 Cu 2 I 5 micro-wires, the photodetector exhibits an ultra-high polarization sensitivity of 4.45. Moreover, the photodetector can keep nearly the identical capability even after 40 days exposure in the open air. This work reveals the potential of Cs 3 Cu 2 I 5 as environmentally-friendly and stable candidates for polarization-sensitive DUV photodetectors, opening up possibilities for developing polarized DUV imaging technology. [ABSTRACT FROM AUTHOR]

The research of broadband photodetectors has been attracting extensive attention because of their great importance and application potentials in numerous fields. In this study, we proposed a perovskite-based photovoltaic broadband photodetector using silicon nanoporous pillar array (Si-NPA) as the hole-transport layer as well as the growth template. By optimizing the conditions of solvent vapors annealing approach, the conformal growth of high-quality CH 3 NH 3 PbI 3 (MAPbI 3) thin films was achieved with a high material integrity, thus enabling a rapid and efficient carrier transport at the MAPbI 3 /Si-NPA interface. The photoresponse analysis reveals that the devices exhibit a high light sensitivity from the deep ultraviolet to the near-infrared region and a pronounced photovoltaic behavior. Typically, a high on/off ratio of 0.82 × 105, a photoresponsivity of 8.13 mA/W, a specific detectivity of 0.974 × 1013 Jones, and fast response speeds of 253.3/230.4 μs were achieved at zero bias under light illumination of 780 nm. Because of the using of air-stable inorganic carrier-transport layers (Si-NPA, ZnO), and the coaxial core/shell heterojunction architecture for a full protection of vulnerable MAPbI 3 active layer from exposure to air ambient, the photodetectors without encapsulation can operate with an excellent stability and repeatability in a wide frequency range over 5000 Hz and continuous light switching (1200 cycles). Even after one-month storage in air ambient, the devices can operate properly with only 8% photocurrent decay. The results obtained provide an effective strategy for the design and development of high-performance broadband photodetectors by combining the advantages of perovskites and functional Si-NPA template. • Si-NPA was used as the functional template to fabricate the perovskite photodetector. • Enhanced performance were obtained compared with the planar Si-based device. • The device is featured by a broadband response with a self-powered ability. • Self-formed coaxial core/shell structure favors for a good device stability. [ABSTRACT FROM AUTHOR]