High-performance Photodetectors Research Articles

Core-shell nanorods film of p-CuZnS/n-TiO2 with boosting interfacial charge separation for sensitive photoelectrochemical photodetector

Copper zinc sulphide (CZS) due to high conductivity, fast photoresponse and good stability has attracted rising attention in optoelectronic field. Constructing heterojunctions with rational energy bands alignment can accelerate carrier separation to improve the performance of CZS-based photoelectric device. Herein, p-CZS/n-TiO2 core-shell nanorods heterojunction film was successfully fabricated for the first time. CZS nanoparticles (NPs) were directly loaded on the surface of TiO2 nanorods (NRs) through a simple chemical bath deposition. Photoelectrochemical (PEC) photodetector based on CZS/TiO2 composite film was designed and interfacial charge kinetics has also been investigated. The CZS/TiO2 PEC device exhibits fast response speed of 95/56 ms, high responsivity of 7.1 mA W-1 and detectivity of 5.6 × 1012 Jones at a bias voltage of 1 V. The light on/off ratio of self-powered CZS/TiO2 PEC device achieves 5.6 × 103, nearly 30.4 times higher than bare CZS PEC device. Furthermore, the photodetection performance of the CZS/TiO2 PEC device can be effectively regulated by light power density and environment conditions, promoting its adaptability in multifarious practical applications. The findings suggest that CZS/TiO2 heterostructure film devices have great potential for high-performance and energy-efficient PEC photodetectors.

Numerical modelling of lead-free perovskite photodetector with GO as ETM and Cz-N as HTM

Photodetectors (PD) are optoelectronic devices that can convert optical signal into electrical signals via the photoelectric effect. A model of CsSn0.5Ge0.5I3 based nip perovskite photodetector (PePd) with graphene oxide (GO) as electron transport material (ETM) and carbazole unit with naphthalene (Cz-N) is used as hole transport material (HTM) are established. The device configuration was analysed using solar cell capacitance simulator-1 dimensional (SCAPS-1D). The effects of absorber thickness, defect density of CsSn0.5Ge0.5I3, metal work function and operating temperature on device architecture have been investigated. For the incident light between 800-820 nm, a maximum responsivity and detectivity 0.65 A/W and 3.6×1013 Jones are obtained respectively. This simulation results will assist in the future research on high-performance lead-free perovskite photodetectors.

Gradient Mo1−xWxSe2 monolayer Alloys: Synthesis and multifunctional applications

With the continuous and rapid development of electronic information technology, the demand for new materials with miniaturization, high integration, high performance, and multifunction is becoming increasingly urgent. However, it is difficult for existing photodetectors based on a single material to achieve multi-functionality while maintaining excellent performance, and the devices based on heterostructures are faced with complex preparation and compatibility problems. In this work, gradient Mo1−xWxSe2 monolayer alloys with high crystal quality have been synthesized by an evaporation-assisted chemical vapor deposition method. The composition of the synthesized Mo1−xWxSe2 monolayer alloys varies gradually with x ranging from 0 to 1. The Mo1−xWxSe2 based photodetector shows superior photoresponse performance in the visible wavelength with maximum responsivity of 26 A/W and external quantum efficiency up to 6320 % under 520 nm laser irradiation. Besides, the Mo1−xWxSe2 device is capable of high-resolution imaging, which can be used as image sensor. Moreover, nonvolatile memory function has also been realized in the device because the band gap of Mo1−xWxSe2 can be effectively adjusted by the gradient distribution of the component and the deep energy levels caused by Se vacancies can be modulated to shallow energy levels. A thrilling discovery is that the gradient Mo1−xWxSe2 alloy device can simulate the biological synapses successfully, including paired-pulse facilitation, short-term plasticity, long-term plasticity and learning process. The realization of high-performance photodetection, visualization, nonvolatile memory and synaptic simulation based on a single gradient crystal offers a new type of material to develop advanced optoelectronic devices with multiple functions.

Ultra-low dark current and high sensitivity lead-free perovskite–like photodetector realized by anti-solvent optimization Cs3Bi2I9 amorphous film

Compared with lead halide perovskite, bismuth-based perovskite has lower toxicity and air stability, demonstrating enormous potential for application, among them, Cs3Bi2I9 materials has been researched as an alternative to lead-based perovskite for application of optoelectronic devices. It is crucial for the realization of high-performance photodetectors which need high-quality perovskite thin films. Here, we prepared a lead-free, all-inorganic, Cs3Bi2I9 perovskite-like amorphous films by spin coating method, and diethyl ether was added as an anti-solvent at different times of spin-coating. The results show that the homogeneous and dense Cs3Bi2I9 amorphous films can be obtained by adding anti-solvent at 14seconds. Furthermore, Cs3Bi2I9 perovskite-like UV photodetector achieved extremely low dark current around ~pA range, high sensitivity of 1.10×104 was fabricated. Our research shows that the preparation of Cs3Bi2I9 amorphous films by the simple antisolvent-assisted spin-coating method are very promising for optoelectronic device.

Controllable Ultrathin Nickel Nanoislands With Dense Discrete Space Charge Regions: Steering Hole Extraction for High-Performance Underwater Multispectral Weak-Light Photodetection.

Undersea optical communication (UOC) is vital for ocean exploration and military applications. In the dim-light underwater environment, photodetectors must maximize photon utilization by minimizing optical losses and carrier recombination. This can be achieved by integrating ultrathin metal nanostructures with photocatalysts to form Schottky junctions, which enhance charge separation and injection while mitigating metal-induced light shading. The strategic design of discrete metal nanostructures providing numerous high-depth space charge regions (SCRs) without overlap offers a promising approach to optimize hole transport paths and further suppress recombination. Here, a facile phase-separation lithography technique is explored to fabricate tunable ultrathin Ni nanoislands atop n-Si, yielding high-performance photoelectrochemical photodetectors (PEC PDs) tailored for underwater weak-light environments. This results indicate that key determinant of hole extraction behavior is the relationship between the spacing distance of adjacent Ni nanostructures (ds) and twice the SCR radius (Ws). PEC PDs with optimized 8nm ultrathin Ni nanostructures featuring closely but non-overlapping SCRs, exhibit a 55-fold increase in photoresponsivity (2.2mAW-1) and a 128-fold enhancement in detection sensitivity (3.2 × 1011 Jones) at 0V over Ni film, revealing the exceptional stability. Furthermore, this approach enables effective detection across UV-vis-near infrared spectrum, supporting reliable multispectral UOC and underwater imaging capabilities.

Ag@WO3 core-shell nanocomposite for wide range photo detection.

This study successfully synthesized high-performance photodetectors based on Ag-WO3 core-shell heterostructures using a simple and economical two-step pulsed laser ablation in water method and has investigated the electrical characteristics of the Ag@WO3 nanocomposite heterojunction. The Hall effect tests indicate that the synthesized Ag@WO3 exhibits n-type conduction with a Hall mobility of 1.25 × 103 cm2V-1S-1. Dark current-voltage properties indicated that the created heterojunctions displayed rectification capabilities, with the highest rectification factor of around 1.71 seen at a 5V bias. A photodetector's responsivity reveals the existence of two response peaks, which are situated in the ultraviolet and visible region. The photodetector demonstrates a rapid response time of less than 100ms. The detectivity values for wavelengths of 350nm and 490nm were 35 × 1013 Jones and 28 × 1013 Jones, respectively. The n-Ag-WO3/n-Si photodetector achieved a maximum EQE of 11.5% in the ultraviolet wavelength when subjected to 3V and illuminated with 350nm (26 mW/cm2) light. The devices demonstrate rapid switching behavior with a rise time of 0.32s and a fall time of 0.33s. The time-dependent light response of a photodetector under illumination at 26 mW/cm2 is seen at a bias of 3V. The light exhibits a rise and decay duration of 15s, while the photocurrent gain is measured at 9µA. The photocurrent of devices exhibited a positive correlation with the incoming light intensity, suggesting that the junction has the potential to function as a photo detector.

Low-Temperature Fabrication of Stable Black-Phase CsPbI3 Perovskite Flexible Photodetectors Toward Wearable Health Monitoring.

Flexible wearable optoelectronic devices fabricated from organic-inorganic hybrid perovskites significantly accelerate the development of portable energy, biomedicine, and sensing fields, but their poor thermal stability hinders further applications. Conversely, all-inorganic perovskites possess excellent thermal stability, but black-phase all-inorganic perovskite film usually requires high-temperature annealing steps, which increases energy consumption and is not conducive to the fabrication of flexible wearable devices. In this work, an unprecedented low-temperature fabrication of stable black-phase CsPbI3 perovskite films is demonstrated by the in situ hydrolysis reaction of diphenylphosphinic chloride additive. The released diphenyl phosphate and chloride ions during the hydrolysis reaction significantly lower the phase transition temperature and effectively passivate the defects in the perovskite films, yielding high-performance photodetectors with a responsivity of 42.1A W-1 and a detectivity of 1.3 × 1014Jones. Furthermore, high-fidelity image and photoplethysmography sensors are demonstrated based on the fabricated flexible wearable photodetectors. This work provides a new perspective for the low-temperature fabrication of large-area all-inorganic perovskite flexible optoelectronic devices.

Preparation of High-performance BaTiO3 Nanoparticles-embedded Porous Silicon Photodetectors by Electrochemical Etching and Laser Ablation in Liquid

Preparation of High-performance BaTiO3 Nanoparticles-embedded Porous Silicon Photodetectors by Electrochemical Etching and Laser Ablation in Liquid

Comparative Analysis of Thin and Thick MoTe2 Photodetectors: Implications for Next-Generation Optoelectronics

Due to its outstanding optical and electronic properties, molybdenum ditelluride (MoTe2) has become a highly regarded material for next-generation optoelectronics. This study presents a comprehensive, comparative analysis of thin (8 nm) and thick (30 nm) MoTe2-based photodetectors to elucidate the impact of thickness on device performance. A few layers of MoTe2 were exfoliated on a silicon dioxide (SiO2) dielectric substrate, and electrical contacts were constructed via EBL and thermal evaporation. The thin MoTe2-based device presented a maximum photoresponsivity of 1.2 A/W and detectivity of 4.32 × 108 Jones, compared to 1.0 A/W and 3.6 × 108 Jones for the thick MoTe2 device at 520 nm. Moreover, at 1064 nm, the thick MoTe2 device outperformed the thin device with a responsivity of 8.8 A/W and specific detectivity of 3.19 × 109 Jones. Both devices demonstrated n-type behavior, with linear output curves representing decent ohmic contact amongst the MoTe2 and Au/Cr electrodes. The enhanced performance of the thin MoTe2 device at 520 nm is attributed to improved carrier dynamics resulting from effective electric field penetration. In comparison, the superior performance of the thick device at 1064 nm is due to sufficient absorption in the near-infrared range. These findings highlight the importance of thickness control in designing high-performance MoTe2-based photodetectors and position MoTe2 as a highly suitable material for next-generation optoelectronics.

High-Performance Ga2O3 Solar-Blind Photodetector Based on Thermal Oxidized Ga Buffer-Layer.

High-performance Ga2O3 solar-blind photodetectors are critical for applications due to their selective solar-blind ultraviolet sensitivity. The quality of the Ga2O3 film has a significant impact on the performance of photodetectors. This study presents an innovative approach to enhancing the quality of Ga2O3 films through the introduction of a naturally graded buffer layer, which is formed by the oxidation of a metallic Ga film and significantly improves interface stability by accommodating lattice mismatches and reducing defects. The structural and compositional characteristics of Ga2O3 films were comprehensively analyzed using UV-vis (ultraviolet-visible) spectroscopy, AFM (Atomic Force Microscope), PL (Photoluminescence Spectroscopy), TEM (Transmission Electron Microscope), and XPS (X-ray Photoelectron Spectroscopy). The photodetectors fabricated from these films demonstrate responsivity of 99.8 mA/W and a solar-blind UV/UV ratio of 1.17 × 103, with significant improvement compared to direct deposited films. This research highlights the potential of natural buffering layers to advance the performance of Ga2O3-based solar-blind UV detectors.

CsPbBr3 perovskite quantum dots/p-GaN heterojunction for ultraviolet-visible spectrum photodetectors

All-inorganic perovskites have attracted increasing attention because of their strong environmental stability and excellent photoelectric properties. However, the limited spectral response range of perovskite photodetectors restricts them in practical applications. In this work, an ultraviolet–visible photodetector with a wide spectral response and a high responsivity was prepared by constructing a CsPbBr3 quantum dots (QDs)/p-GaN heterojunction. The type-II energy band alignment formed by the heterojunction is conducive to the transport of photogenerated carriers, resulting in a high responsivity. Under certain conditions, the device can obtain responsivity values of 5 A/W and 850 mA/W under 350 and 725 nm illumination, respectively, which are comparable to those of other perovskite-based photodetectors. In addition, the photoresponse mechanism of the device is revealed through first-principles calculations of the heterojunction and the device. The enhanced light absorption of the heterojunction and the special band bending under different bias voltages improve the photoelectric performance of the device. This work can provide valuable insights into high-performance photodetectors based on all-inorganic perovskite QDs heterojunctions in terms of band regulation and device performance improvement.

Structure Engineering of Ga2O3 photodetectors: A Review

Abstract Deep ultraviolet (DUV) photodetectors play important roles in the modern semiconductor industry due to their diverse applications in critical fields. Wide bandgap semiconductor Ga2O3 is considered as one promising material for highly sensitive DUV photodetectors. However, the high responsivity of Ga2O3 DUV photodetectors always comes at the expense of its response speed. Material engineering for high-quality Ga2O3 materials can optimize the photoresponse performance but at the cost of much more complex process. Structure engineering can efficiently improve the performance of Ga2O3 photodetectors based on various physical mechanisms. Owing to the increased modulation probabilities, part schemes of structure engineering even alleviate the tough requirements on Ga2O3 material quality for high-performance DUV photodetectors. This article reviews the recent efforts in optimizing the performance of Ga2O3 photodetectors through structure engineering. Firstly, photodetectors based on Ga2O3 nanostructures and metasurface structures with nanometer size effect are discussed. In addition, junction structures of Ga2O3 photodetectors, which effectively promote carrier separation in the depletion region, are summarized based on a classification of Schottky junction, heterojunction, phase junction, etc. Besides, Ga2O3 avalanche photodiodes, offering ultra-high gain and responsivity, are focused as a promising prototype for commercialization. Furthermore, field effect phototransistors, based on which the scalability and low power performance of Ga2O3 photodetectors have been well proven, are analyzed in detail. Moreover, auxiliary-field configurations with extra tunable dimensions for Ga2O3 photodetectors are introduced. Finally, we conclude this review and discuss the main challenges of Ga2O3 DUV photodetectors from our perspective.

Terminal Fluorination Modulates Crystallinity and Aggregation of Fully Non-Fused Ring Electron Acceptors for High-Performance and Durable Near-Infrared Organic Photodetectors.

High dark current density (Jd) severely hinders further advancement of near-infrared organic photodetectors (NIR OPDs). Herein, we tackle this grand challenge by regulating molecular crystallinity and aggregation of fully non-fused ring electron acceptors (FNREAs). In contrast to the general trend in terminal halogenation of electron acceptors, TBT-V-F, featuring fluorinated terminals, notably demonstrates crystalline intensification and a higher prevalence predominance of J-aggregate compared to its chlorinated counterpart (TBT-V-Cl). The amalgamation of advantages confers TBT-V-F-based OPDs with more organized active layer morphology and denser molecular packing, resulting in improved charge transport, decreased energetic disorder, and reduced trap density. Consequently, the corresponding self-powered OPDs exhibit a 40-fold decrease in Jd, a remarkable increase in detectivity (D*sh), faster response time, and superior thermal stability compared to TBT-V-Cl-based OPDs. Further interfacial optimization results in an ultra-low Jd of 7.30´10-12 A cm-2 with D*sh over 1013 Jones in 320-920 nm wavelength and a climax of 2.2´1014 Jones at 800 nm for the TBT-V-F-based OPDs, representing one of the best results reported to date. This work paves a compelling material-based strategy to suppress Jd for highly sensitive NIR OPDs, while also illustrates the viability of FNREAs in construction of stable and affordable NIR OPDs for real-world applications.

Self-Trapped Excitons in 3R ZnIn2S4 with Broken Inversion Symmetry for High-Performance Photodetection.

Exploring novel materials with intrinsic self-trapped excitons (STEs) is crucial for advancing optoelectronic technologies. In this study, 2D 3R-phase ZnIn2S4, featuring broken inversion symmetry, is introduced to investigate intrinsic STEs. This material exhibits a broadband photoluminescence (PL) emission with a full width at half maximum of 164nm and a large Stokes shift of ≈0.6eV, which arises from the distortion of [ZnS4]6- tetrahedral unit induced by the symmetry breaking and strong electron-phonon coupling. The photophysical properties of the STEs exhibit a high Huang-Rhys factor (15.0), rapid STEs formation time (166fs), and extended STEs lifetime (1039ps), as demonstrated by experimental evidence from temperature-dependent PL, Raman spectroscopy, and ultrafast absorption spectroscopy. Additionally, STE-induced photoconductiveeffect is elucidated, indicating that intrinsic STEs in 3R-ZnIn2S4 can provide a synergistic effect that enhances absorption capacity, localization, and lifetime by capturing the self-trapped hole state. Consequently, the 2D 3R-ZnIn2S4 photodetector exhibits remarkable broad-spectrum photosensitivity, including a photo-switching ratio of 11286, response times of less than 0.6ms, responsivity of 15.2AW-1, detectivity of 1.02×10¹¹ Jones, and external quantum efficiency of 5032% under 375nm light. These findings provide new ideas for exploring materials with intrinsic STEs to achieve novel high-performance photodetector applications.

Enabling Fast Photoresponse in Hybrid Perovskite/MoS2 Photodetectors by Separating Local Photocharge Generation and Recombination.

Interfacing CH3NH3PbI3 (MAPbI3) with 2D van der Waals materials in lateral photodetectors can suppress the dark current and driving voltage, while the interlayer charge separation also renders slower charge dynamics. In this work, we show that more than one order of magnitude faster photoresponse time can be achieved in MAPbI3/MoS2 lateral photodetectors by locally separating the photocharge generation and recombination through a parallel channel of single-layer MAPbI3. Photocurrent (Iph) mapping reveals electron diffusion lengths of about 20 μm in single-layer MAPbI3 and 4 μm in the MAPbI3/MoS2 heterostructure. The illumination-power scaling of Iph and time-resolved photoluminescence studies point to the dominant roles of the heterostructure region in photogeneration and single-layer MAPbI3 in charge recombination. Our results shed new light on the material design that can concurrently enhance photoresponsivity, reduce driving voltage, and sustain high operation speed, paving the path for developing high-performance lateral photodetectors based on hybrid perovskites.

High-performance flexible and broadband photodetectors on paper substrates using FeSnS bimetallic sulfide nanosheets

Advancements in technology have made it easier to construct flexible broadband photodetectors for wearable devices, improving light harvesting and detecting capabilities. This work described a new study that used bimetallic sulfide nanosheets (FeSnS) to produce flexible and broadband photodetectors on paper substrates using hand-print method. A simple, economical, one-step hydrothermal technique was employed to synthesise FeSnS materials, which were characterised using XRD, UV–Vis Spectroscopy, FESEM, EDS, XPS, and UPS. Photodetection tests found that 2-FeSnS (Fe at 2 wt%) outperformed similar work on paper-based devices, with a responsivity of 32.4 mA/W under a 470 nm incident wavelength, high specific detectivity, and a response time of 1.16 s. Durability and flexibility testing validated the robustness of the device. The use of a simple hydrothermal synthesis and hand-print fabrication method to create high-performance, eco-friendly, and flexible photodetectors is novel, expanding their potential applications in wearable electronics, environmental monitoring, and low-cost disposable sensing platforms.

High-performance single SiC nanocable-based plasmonic photodetectors for ultraviolet communication systems

High-performance single SiC nanocable-based plasmonic photodetectors for ultraviolet communication systems

CuO and MoS₂ Nanocomposite-Based High-Performance Wideband Photodetector

CuO and MoS₂ Nanocomposite-Based High-Performance Wideband Photodetector

Metamaterials for high-performance photodetectors

Metamaterials for high-performance photodetectors

Freestanding ZnO Nanowire Films Derived from Carbon Nanotube Template: Implications for High-Performance UV Photodetectors

Freestanding ZnO Nanowire Films Derived from Carbon Nanotube Template: Implications for High-Performance UV Photodetectors