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High-performance WSe2 photodetector based on laser-induced p-n junction
摘要： Two-dimensional (2D) heterojunctions exhibit many unique features in nanoelectronic and optoelectronic devices. However, heterojunction engineering requires complicated alignment process and some defects are inevitably introduced during material preparation. In this work, a laser scanning technique is used to construct a lateral WSe2 p-n junction. The laser-scanned region shows a p-type behavior and the adjacent region is electrically n-doped with a proper gate voltage. The laser-oxidized product WOx is found to be responsible for this p-type doping. After laser scanning, WSe2 displays a change from ambipolar to unipolar p-type property. A significant photocurrent emerges at the p-n junction. Therefore, a self-powered WSe2 photodetector can be fabricated based on this junction, which presents a large photoswitching ratio of 106, high photoresponsivity of 800 mA W-1 and short photoresponse time with long-term stability and reproducibility. Therefore, this selective laser-doping method is prospective in future electronics applications.
关键词： photodetector,p-n junction,laser-doping,tungsten diselenide,oxidation product
更新于2025-09-11 14:15:04
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Photodetector based on heterostructure of two-dimensional WSe2/In2Se3
摘要： Heterojunctions formed by two-dimensional (2D) layered semiconducting materials have been studied extensively in the past several years. These van der Waals (vdW) structures have shown great potential in future electronic and optoelectronic devices. However, the optoelectronic performance of these devices is limited by the indirect band gap of the multilayer materials and low light absorption of single layer materials. Here, we fabricate photodetectors based on heterojunctions composed of n-type multilayer α-Indium Selenide (In2Se3) and p-type Tungsten Diselenide (WSe2) for the first time. The direct band gap of multilayer α-In2Se3 and type-II band alignment of the WSe2/In2Se3 heterojunction enable high optoelectronic performance of the devices at room temperature in the air. Without light illumination, the dark current is effectively suppressed to 10-13 A under -1 V bias and a high rectification ratio of 7.37×103 is observed. Upon laser illumination with the wavelength of 650 nm, the typical heterojunction device exhibits a photocurrent on/off ratio exceeding 1.24×105, a maximum photo responsivity of 26 mA/W and short photoresponse time of 2.22 ms. Moreover, the heterojunction photodetectors show obvious light response in the wavelength range from 650 nm to 900 nm. The present 2D vdW heterojunctions composed of direct band gap multilayer materials show great potential in future optoelectronic devices.
关键词： In2Se3,photodetector,two-dimensional materials,WSe2,direct band gap materials,heterojunction
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Dark Current Analysis of Vertical p-i-n Photodetectors on a Germanium-on-Insulator Platform
摘要： Dark current of vertical p-i-n photodetectors on a germanium-on-insulator platform was analyzed. The activation energy was found to be from 0.15 to 0.36 eV under reserve bias. The dark current generation was interpreted by Shockley-Read-Hall and trap-assisted-tunneling effects. This work provides the interpretation on germanium-on-insulator photodetectors and suggests the alternative to suppress the dark current generation for Si-based Ge photodetectors.
关键词： Ge-on-insulator,photodetector,activation energy,direct wafer bonding
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Cancun (2018.8.29-2018.8.31)] 2018 IEEE 15th International Conference on Group IV Photonics (GFP) - Accelerating Passive and Active Silicon Photonics Design using Multiple Numerical Techniques
摘要： This work compares three numerical techniques for modeling the optics of passive and active silicon photonic devices. A comparison of computation time revealed that a judicious choice of technique can lead to the reduction of design cycle time by orders of magnitude.
关键词： Waveguide Photodetector,Silicon Photonics,Spot size converter,EME,MMI,BPM,FDTD
更新于2025-09-10 09:29:36
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Femto-Farad Optoelectronic Coupling and Low-Latency Nanophotonic Computing
摘要： We demonstrate that the capacitance of OE/EO conversion devices, such as photo-detectors and electro-optic modulators, can be reduced down to a fF level by use of photonic crystals. This enables us to drastically reduce the energy efficiency of OE/EO conversion. We show that on-chip high-speed photo-receivers can be operated without any electrical power, and pseudo-all-optical-nonlinear devices can be realized by a combination of a fF photodetector and a fF electro-optic modulator. Integrated nanophotonics technologies, including those fF-optoelectronic devices, will enable optical pass-gate logic circuits for low-latency optical computation. We present our novel designs for various examples including optical full adder circuits. In addition, we show linear optic gates for logic functions which enable extremely small latency.
关键词： photodetector,nanophotonics,optical computing,optical transistor,electro-optic modulator,photonic crystal
更新于2025-09-10 09:29:36
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The Au/Cu2WSe4/p-Si photodiode: Electrical and morphological characterization
摘要： Cu2WSe4 nanosheets were synthesized by the hot-injection method and put as interfacial layers between Au metal and p-Si by spin coating technique to investigate their photoresponse and capacitor properties via I-V and C-V measurements, respectively. The XRD were operated to confirm crystalline structure of the Cu2WSe4. The TEM image revealed that the crystalline nanosheet structures of the Cu2WSe4. The I-V measurements were performed under dark and light illumination in the range 20 mWe100 mW light intensities with 20 mW interval. In addition, some diode parameters such as ideality factor, barrier height and series resistance were extracted via a various method and discussed in the details. The C-V measurements were employed for various frequency and voltages. The C-V characteristics of the device confirmed the strong dependence on the frequency and voltage. The results imparted that Au/Cu2WSe4/p-Si can be employed for photodiode, photodetector and capacitor applications.
关键词： Copper tungsten selenide,Photodetector,Schottky devices,Cu2WSe4,Au/Cu2WSe4/p-Si photodiode
更新于2025-09-10 09:29:36
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Enhanced Detectivity and Suppressed Dark Current of Perovskite-InGaZnO Phototransistor via PCBM Interlayer
摘要： Hybrid phototransistors based on InGaZnO (IGZO) metal oxide thin film transistor (TFT) and photoabsorbing capping layer such as perovskite (MAPbI3) is a promising low-cost device for developing advanced X-ray and UV flat panel imager. However, it is found that the introduction of MAPbI3 inevitably damages the IGZO channel layer during fabrication, leading to deteriorated TFT characteristics such as off current rising and threshold voltage shift. Here, we report an effective approach for improving the performance of the perovskite-IGZO phototransistor by inserting a PCBM or PCBM:PMMA interlayer between the patterned MAPbI3 and the IGZO. The interlayer effectively prevents the IGZO from damaging by the perovskite fabrication process, while allowing efficient charge transfer for photo sensing. In this configuration, we have achieved a high detectivity (1.35 × 1012 Jones) perovskite-IGZO phototransistor with suppressed off-state drain current (~10 pA) in the dark. This work points out the importance of interface engineering for realizing higher performance and reliable heterogeneous phototransistors.
关键词： IGZO,interlayer,phototransistor,perovskite,photodetector
更新于2025-09-10 09:29:36
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The effect of morphology and functionalization on UV detection properties of ZnO networked tetrapods and single nanowires
摘要： Rapid detection and fast response of nanoelectronic devices based on semiconducting oxides is nowadays a modern and stringent subject of research. Device performances depend mainly on the morphologies of the metal oxide nanostructures. In the scope of this work, the influence of the structural morphology of three-dimensional (3-D) ZnO nano- and microstructured networks on the room temperature UV detection properties is studied in detail. We show that the formation of multiple potential barriers between the nanostructures, as well as the diameter of the nanostructures, which is in the same order of magnitude as the Debye length, strongly influence the UV sensing properties. Consequently, 3-D ZnO networks consisting of interconnected ultra-long wire-like tips (up to 10 μm) and with small wire diameters of 50–150 nm, demonstrated the highest UV sensing performances (UV response ratio of ～3100 at 5 V applied bias voltage). Furthermore, we demonstrate the possibility of substantially increasing the UV sensing performances of individual ZnO nanowire (NW) (diameter of ～50 nm) by surface functionalization with carbon nanotubes (CNTs), showing high response ratio (～60–50 mW/cm2), as well as fast response (～1 s) and recovery (～1 s) times. The obtained results thus provide a platform with respect to the next generation of portable UV radiation detectors based on semiconducting oxide networks.
关键词： CNT,UV photodetector,ZnO,Device,Individual nanostructures,Nanosensor
更新于2025-09-10 09:29:36
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Engineering Interface-Dependent Photoconductivity in Ge <sub/>2</sub> Sb <sub/>2</sub> Te <sub/>5</sub> Nanoscale Devices
摘要： Phase change materials are increasingly being explored for photonics applications, ranging from high resolution displays to artificial retinas. Surprisingly, our understanding of the underlying mechanism of light-matter interaction in these materials has been limited to photothermal crystallization, because of its relevance in applications such as re-writable optical discs. Here we report a photoconductivity study of nanoscale thin films of phase change materials. We identify strong photoconductive behaviour in phase change materials, which we show to be a complex interplay of three independent mechanisms: photoconductive, photo induced-crystallization and photo-induced-thermoelectric effects. We find these effects also congruously contribute to a substantial photovoltaic effect, even in notionally symmetric devices. Notably, we show that device engineering plays a decisive role in determining the dominant mechanism; the contribution of the photothermal effects to the extractable photocurrent can be reduced to < 0.4 % by varying the electrodes and device geometry. We then show that the contribution of these individual effects to the photoresponse is phase-dependent with the amorphous state being more photoactive than the crystalline state and that a reversible change occurs in the charge transport from thermionic to tunnelling during phase transformation. Finally we demonstrate photodetectors with an order of magnitude tuneability in photodetection responsivity and bandwidth using these materials. Our results provide insight to the photo-physics of phase change materials and highlight their potential in future opto-electronics.
关键词： Mixed-Mode Operation,Photothermal effects,Tuneable Photodetector,Phase Change Materials,Photoconductivity
更新于2025-09-10 09:29:36
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Catalyst-Free Growth of a Zn2GeO4 Nanowire Network for High-Performance Transfer-Free Solar-Blind Deep UV Detection
摘要： Solar-blind deep-ultraviolet (DUV) photodetectors have attracted wide attention because of their extensive military and civil applications. The ternary oxide Zn2GeO4 is an ideal material with a wide bandgap (Eg = 4.69 eV). In this work, DUV photodetectors based on a ternary Zn2GeO4 nanowire (NW) network were fabricated on SiO2/Si substrates. Reactive ion etching of the SiO2/Si wafer was used to grow the NW network to avoid contamination of the Au catalyst during synthesis of the Zn2GeO4 NW network via high-temperature chemical vapor deposition. Photodetectors based the Zn2GeO4 NW revealed fast response and recovery times, which is attributed to the unique cross-junction barrier-dominated conductance of the NW network. Results showed that the ternary oxide-based NW network is an ideal building block for nanoscale solar-blind photodetectors with superior performance.
关键词： Zn2GeO4 nanowire,ultraviolet photodetector,catalyst-free
更新于2025-09-10 09:29:36