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Ultra-Broadband, High Speed, and High-Quantum-Efficiency Photodetectors Based on Black Phosphorus
摘要： Black phosphorus (BP), a narrow band gap semiconductor without out-of-plane dangling bonds, has shown promise for broadband and integrable photodetector applications. Simultaneously exhibiting high speed and high-efficiency operation, however, remains a critical challenge for current BP-based photodetectors. Here, we demonstrate a photodetector based on the BP-based van der Waals heterostructures. The developed photodetector enables broadband responses in the visible to mid-infrared range with external quantum efficiency (EQE) ranging from 20% to 52% at room temperature. These results together with noise measurements indicate the photodetector can detect light in the pico-watt range. Furthermore, the demonstrated BP detector has ultrafast rise (1.8 ns) and fall (1.68 ns) times, and its photoresponse exhibits reproducible switching behavior even under consecutive and rapid light intensity modulations (2100 cycles, 200 MHz), as indicated by the eye-diagram measurement. By leveraging these features, we show our BP heterostructures can be configured as a point-like detector in a scanning confocal microscopy, useful for mid-infrared imaging applications.
关键词： van der Waals heterostructures,mid-infrared imaging,Black phosphorus,high speed,broadband photoresponses,photodetector
更新于2025-09-11 14:15:04
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Epitaxy || Epitaxy and Device Properties of InGaAs Photodetectors with Relatively High Lattice Mismatch
摘要： In this chapter, our works on the developments of wavelength-extended InGaAs photodetectors with cutoff wavelength >1.7 μm are reviewed. Various InGaAs/InAlAs p-i-n heterojunction structures have been grown on InP and GaAs substrates by gas source molecular beam epitaxy, some details on the InGaAs photodetector structures and the techniques of metamorphic buffer layer such as linearly, step, and one-step continuously InAlAs graded buffer, and dislocation restraint methods of compositional overshoot and digital alloy are introduced. The material characteristics and device properties were evaluated by atomic force microscopy, high-resolution X-ray diffraction and reciprocal space mapping, cross-sectional transmission electron microscopy, and current-voltage measurements, etc. The results provide clues to the development of metamorphic device structures on lattice-mismatched material systems.
关键词： photodetector,X-ray diffraction,InGaAs,metamorphic,atomic force microscopy,photoluminescence,lattice mismatch
更新于2025-09-11 14:15:04
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Design of Microdisk-Shaped Ge on Si Photodetector with Recess Structure for Refractive-Index Sensing
摘要： In this paper, we introduce a disk-shaped Ge-on-Si photodetector for refractive-index difference sensing at an operating wavelength of 1550 nm. For the implementation of a small-scale sensor, a Ge layer was formed on top of a Si layer to increase the absorption coefficient at the expense of the light-detection area. Additionally, the sensor had a ring waveguide structure along the edge of the disk formed by a recess into the inner part of the disk. This increased the interaction between the dominant optical mode traveling along the edge waveguide and the refractive index of the cladding material to be sensed, and conclusively increased detection sensitivity. The simulation results show that the proposed sensor exhibited a detection sensitivity of >50 nm/RIU (Refractive Index Unit), a quality factor of approximately 3000, and a minimum detectable refractive index change of 0.95 × 10?2 RIU with a small disk radius of 3 μm. This corresponds to 1.67 times the sensitivity without a recess (>30 nm/RIU).
关键词： refractive index sensor,disk resonator,silicon on insulator,germanium photodetector
更新于2025-09-11 14:15:04
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Quantum Multibody Interactions in Halide-Assisted Vapor-Synthesized Monolayer WSe <sub/>2</sub> and Its Integration in a High Responsivity Photodetector with Low-Interface Trap Density
摘要： Among the two-dimensional (2D) transitional-metal dichalcogenides, monolayer (1L) tungsten diselenide (WSe2) has recently attracted a great deal of interest because of its direct band gap and tunable charge transport behavior, making it attractive for a variety of electronic and optoelectronic applications. Controlled and efficient synthesis of 1L WSe2 using chemical vapor deposition (CVD) is often challenging because of the high temperatures required to generate a steady flux of tungsten atoms in the vapor phase from the oxide precursors. Here, the use of halide-assisted low-pressure CVD with NaCl helps to reduce the growth temperature to ～750 °C, which is lower than the typical temperatures needed with conventional CVD for realizing 1L WSe2. Moreover, we experimentally probed the quantum multibody interactions in 1L WSe2 ascribed to excitons, trions, and other localized states by analyzing the temperature-dependent photoluminescence spectra, where such multibody interactions govern the intrinsic electronic and optoelectronic properties of 1L WSe2 for device platforms. The role of the metal?2D semiconductor interface is also critical to realize high-performance devices. In this study, a 1L WSe2-based photodetector was fabricated using Al contacts, which shows a high photoresponsivity, and the interface-state density Dit of the Al/WSe2 junction was computed to be the lowest reported to date ～3.45 × 1012 cm?2 eV?1. Our work demonstrates the tremendous potential of WSe2 to open avenues for state-of-the-art electronic, optoelectronic, and quantum-optoelectronic devices using scalable synthesis routes.
关键词： transitional-metal dichalcogenides,photodetector,tungsten diselenide (WSe2),two-dimensional (2D) materials,quantum multibody interactions,interface-state density,chemical vapor deposition (CVD)
更新于2025-09-11 14:15:04
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High-bandwidth InGaN self-powered detector arrays toward MIMO visible light communication based on micro-LED arrays
摘要： This work reports the use of the chip-based GaN-based micro-LED (μLED) arrays for multifunctional applications as micro-display, data transmitters, photodetectors and solar cells. The functions of display and transmitter have been reported, and particularly we experimentally demonstrated that μLED arrays could be used as self-powered, high-performance and wavelength-selective photodetectors (PDs) enabling high-speed multiple-input multiple-output (MIMO) visible light communications (VLC) under on-off keying (OOK) modulation scheme using 405 nm violet laser diodes (LDs) as transmitters. The optoelectronic and communication characteristics of the μLED-based PDs with diameters of 40 μm, 60 μm and 100 μm were systematically studied. The optoelectronic analysis shows superior performances of μLED-based PDs at 405 nm wavelength compared with other previously reported GaN-based PDs. Under a bias voltage of -5 V, the comparable peak responsivities of 0.27, 0.31 and 0.24 A/W, specific detectivities of 1.1 × 1011, 2.3 × 1012 and 2.1 × 1012 cm ? H1/2 ? W-1, and linear dynamic ranges (LDRs) of 152, 162 and 164 dB were achieved for 40-μm, 60-μm and 100-μm μLEDs, respectively. Even at zero-bias, i.e. self-powered mode, we have achieved high peak responsivities of 0.24, 0.29 and 0.21 A/W, high specific detectivities of 7.5 × 1012, 1.5 × 1013 and 1.3 × 1013 cm?H1/2?W-1 and high LDR up to 186, 196 and 197 dB for 40-μm, 60-μm and 100-μm μLEDs, respectively. The μLEDs could also be used to harvest the optical energy of the system, working as solar cells. The μLED-based PD arrays were tested as receivers in VLC system to implement high-speed parallel communication, which yields maximum data rates of 180 Mbps, 175 Mbps and 185 Mbps for a single 40-μm, 60-μm and 100-μm μLED-based PDs at a distance of 1 m with BERs of 3.5 × 10-3, 3.7 × 10-3 and 3.5 × 10-3, respectively. Furthermore, 2 × 2 MIMO parallel VLC system was achieved to increase the VLC data rate, which suggests the potential of using large μLED-based PD arrays for multiple Gbps and even Tbps VLC applications.
关键词： photodetector array,visible light communication,Micro-LED (μLED),multiple-input and multi-output (MIMO),self-powered
更新于2025-09-11 14:15:04
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Piezoelectric Modulation of Broadband Photoresponse of Flexible Tellurium Nanomesh Photodetectors
摘要： Flexible photodetector shows great potential applications in intelligent wearable devices, health monitoring, and biological sensing. In this work, single crystal β-tellurium nanowires were grown on flexible muscovite by molecular beam epitaxy, constructing high-density ordered nanomesh structure. The prepared photodetectors based on tellurium nanomesh exhibit excellent mechanical flexibility, fast response in a broad range from ultraviolet to near-infrared, and good photosensitivity. We found that the flexible photodetectors with Shottky contact drastically suppressed dark current, while the response speed was lowered in comparison to the devices with ohmic contact, as holes would take long time to tunnel through the Shottky barrier between metal and p-type Te. Moreover, photoresponse of flexible Shottky photodetectors can be modulated by piezoelectricity of tellurium, and pronounced photocurrent increase after many times of bend. Under external stress, polarization charges could tune Shottky barrier height of the metal/tellurium, resulting in variation of photocurrent. The research not only explores the broadband photoresponse and piezoelectric effect of tellurium nanomesh, but also promotes the integration and development of broadband flexible optoelectronic devices.
关键词： tellurium nanomesh,piezoelectric effect,broadband photoresponse,molecular beam epitaxy,flexible photodetector
更新于2025-09-11 14:15:04
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Nucleation promoted synthesis of large-area ReS<sub>2</sub> film for high-speed photodetectors
摘要： Rhenium disulfide (ReS2) is a transition metal dichalcogenide with a layer-independent direct bandgap. Notably, the weak interlayer coupling owing to its T-phase structure enables multi-layer ReS2 to behave similarly to decoupled monolayers. This inherent characteristic makes continuous multi-layer ReS2 film a unique platform for large-area electronic applications. To date, the bulk of work on ReS2 has been conducted using mechanically exfoliated samples or small size flakes (< 1mm2) with no potential for large-scale electronics. A chemical vapor deposition (CVD) synthesis of a large area, continuous ReS2 film directly on a SiO2 substrate is also known to be more challenging compared with that of other 2D materials, such as MoS2 and WS2. This is partly due to its tendency to grow into discrete dendritic structures. In this study, a large-area (> 1 cm2), continuous multilayer ReS2 film is directly synthesized on a SiO2 substrate without any transfer process. The polycrystalline ReS2 film synthesized by this method exhibits one of the fastest photoresponse speeds (0.03 s rise time and 0.025 s decay time) among the reported CVD films. The responsivity Rλ was also the highest among large-area CVD films. The synthesis method for a continuous multilayer ReS2 film is amenable to large-scale integration and will pave the way for practical optoelectronic applications based on 2D layered materials.
关键词： Photodetector,Large-area synthesis,Metal chalcogenides,Chemical vapor deposition,Two-dimensional material,Nucleation promotor
更新于2025-09-11 14:15:04
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A novel approach for preparation of CH3NH3PbBr3 via direct transformation of electrodeposited PbO2 for photodetector application
摘要： Organic–inorganic hybrid perovskites are crystals with efficient light absorption, high charge carrier mobility and long electron/hole diffusion path that have been developed to enhance sunlight energy application. In particular, lead-based compounds by establishing excellent performance in 3rd generation solar cells led to an increased interest in testing them in other areas such as photodetectors, diodes, and transistors. Herein, we report a simple, scalable and versatile fabrication process of CH3NH3PbBr3 layer through electrodeposition technique without using a glove box or a high vacuum system. Measurements demonstrated that a high quality crystalline structure in a pinhole free perovskite layer was obtained. The fabricated photodetector devices made of electrodeposited MAPbBr3 films displayed significant performance with the on/off current ratio of 3 × 106 under white light radiation at 0.1 V bias voltage. Increasing the thickness of photoactive absorber layer up to 1 μm led to 7% external quantum efficiency and 34.4% improvement of EQE compared to 546 nm film.
关键词： photodetector,electrodeposition,MAPbBr3,PbO2,Organic–inorganic hybrid perovskites
更新于2025-09-11 14:15:04
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A vertical structure photodetector based on all‐inorganic perovskite quantum dots
摘要： In this work, the vertical structure photodetector based on CsPbBr3 quantum dots (QDs) with a structure of indium tin oxide (ITO)/zinc oxide (ZnO)/CsPbBr3 QDs/Au is reported. In this device, CsPbBr3 QDs film works as the light‐harvesting layer, and ZnO QDs film acts as the electron transport channel, which can extract the electron efficiently and improve the quality of CsPbBr3 QDs film. As a result, the on/off ratio, detectivity and rise time (decay time) of CsPbBr3/ZnO hybrid photodetector are measured to be 2.4 × 106, 2.25 × 1011, and 62 milliseconds (82 ms) under 0‐V bias. This work inspires the development of vertical structure photodetectors based on the all‐inorganic perovskite QDs.
关键词： zno quantum dot,all‐inorganic perovskite quantum dot,vertical structure photodetector
更新于2025-09-11 14:15:04
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Wearable Gallium Oxide Solar-blind Photodetectors on Muscovite Mica Having Ultra-High Photoresponsivity And Detectivity With Added High Temperature Functionalities
摘要： Wearable Gallium oxide solar-blind photodetector fabricated on muscovite mica is reported for room temperature as well as high temperature operations. The ultra-high photoresponsivity of 9.7 A/W is obtained for 5V applied bias at room temperature under 75 μW/cm2 weak illumination of 270 nm wavelength. The detector enables very low noise equivalent power (NEP) of 9×10-13 W/Hz1/2 and ultra-high detectivity of 2×1012 jones which shows the magnificent detection sensitivity. Further, bending tests are performed for robust utilization of flexible detectors up to 500 bending cycles with each bending radius of 5 mm. After 500 bending cycles, device shows slight photocurrent decrease. The bending performances exhibit excellent potential for wearable applications. Moreover, photocurrent and dark current characteristics above room temperature demonstrate the outstanding functionalities till 523K temperature which is remarkable for flexible photodetectors. The obtained results show the potential of Gallium oxide solar-blind photodetectors at room temperature and high temperatures environments which pave the ways for futuristic smart and flexible sensors.
关键词： photoresponse,Gallium Oxide,Solar-blind photodetectors,detectivity,flexible photodetector,Mica
更新于2025-09-11 14:15:04