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Room temperature low frequency noise in n <sup>+</sup> -InAs/n-InAsSbP/InAs/p-InAsSbP double heterostructure infrared photodiodes
摘要： Low frequency forward current noise as well as the photocurrent noise are studied in InAsSbP/InAs double heterostructure (DH) photodiodes, in the frequency range 1–104 Hz. The photocurrent noise in DH photodiodes is signi?cantly lower than in single heterostructure (SH) photodiodes. The forward current noise in a DH diode exhibiting the 1/f frequency dependence is also much lower than that in SH diodes. However, in some DH diodes, it is the generation-recombination mechanism that provides the dominant contribution to the forward current noise; in this case the noise level is signi?cantly higher. At suf?ciently high forward current densities, the noise decreases with current. The observed generation-recombination noise spectrum cannot be described within the conventional theory.
关键词： InAs photodiodes,low frequency noise,forward bias,photocurrent noise,Mid-IR photodetectors
更新于2025-09-19 17:13:59
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InGaAs/graphene infrared photodetectors with enhanced responsivity
摘要： High responsivity is a vital aim of photodetectors research. Based on the photogating effect, ultra-high responsivity can be realized by combining the high mobility of graphene and strong light absorption of other materials. Due to long carrier lifetime and low mobility, quantum dots(QDs) are usually used to form hybrid photodetectors with graphene. However, hybrid photodetectors of graphene with materials possessing higher mobility are rarely studied at present. In this paper, the hybrid photodetector of graphene and InGaAs is studied. We fabricated and measured pure InGaAs photodetectors, hybrid photodetectors of the whole graphene on InGaAs surface and hybrid photodetectors of graphene nanoribbons(GNRs) on InGaAs surface. It is found that, compared to pure InGaAs photodetectors, the responsivity of the whole graphene on InGaAs surface devices increases by 14.7 times, which is 7.66 A W?1, and the response time is twice faster. We also found that the negative back voltage can increase the photocurrent by modulating the Fermi energy of graphene and barrier height of the hybrid photodetectors. The illuminated area effect on various devices area was discussed in this study. In terms of theoretical mechanization, as high mobility materials, both graphene and InGaAs could generate and transport carriers in this hybrid photodetector under optical illumination. The photoexcited holes in InGaAs enter graphene while the photoexcited electrons in graphene enter InGaAs due to the built-in ?eld, which leads to a charge build-up on both sides of the junction and a strong photogating effect on the channel conductance. The results of this study are of novel signi?cance for the development of infrared detectors based on graphene.
关键词： infrared photodetectors,responsivity,graphene,InGaAs
更新于2025-09-19 17:13:59
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Higha??Performance Ultravioleta??Visible Lighta??Sensitive 2Da??MoS <sub/>2</sub> /1Da??ZnO Heterostructure Photodetectors
摘要： Two-dimensional (2D) transition-metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) have recently attracted extensive interest for building future optoelectronic devices. However, the limited light absorption, low photoresponsivity and slow response speed in visible range inhibit their further application. Here, we proposed a promising approach to realize the high-performance photodetectors (PDs) by constructing 2D-MoS2 flake/1D-ZnO nanowire mixed-dimensional heterostructures. The integration of 1D-ZnO on p-type or n-type MoS2 to form the mixed-dimensional 2D-MoS2/1D-ZnO heterostructure PDs not only broadens the light response range, but also improves the photoresponsivity and response time of 2D-MoS2 flakes. Under the 365 nm light illumination, the photoresponsivity, external quantum efficiency and response time of p-MoS2/n-ZnO PDs are as high as 24.36 A/W, 8.28 × 103 % and 0.9 s, respectively. Under 532 nm light illumination, the photoresponsivity, external quantum efficiency and response time are estimated to be 0.35 A/W, 80.9 % and 140 ms, respectively. These properties are superior or comparable to the performance of other reported 2D-MoS2 flake PDs. This work provides a possible strategy for the realization of high-performance optoelectronic devices by the integration of 2D-MoS2 and 1D-ZnO to form mixed-dimensional heterostructures.
关键词： zinc oxide,photodetectors,Heterostructure,low-dimension,molybdenum disulfide
更新于2025-09-19 17:13:59
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Ag nanorods assembled with ZnO nanowalls for near-linear high-response UV photodetectors
摘要： We developed a simple method of sonication combined with annealing treatment method to construct ZnO/Ag heterostructures from Ag nanorods assembled in-situ with ZnO nanowalls, which were then characterized by FESEM, EDS, XRD, XPS, PL, UV-vis spectra. A perfect heterojunction was formed by Ag nanorods inserted into the holes of 3D ZnO nanowalls. Compared with pure ZnO nanowalls, the ZnO/Ag heterostuctures have more vacancy defects and a red shift in absorption. The effects of the working temperature on sensors fabricated with ZnO/Ag heterojunction were investigated. The photodetector demonstrated higher photo response activity as well as a faster response speed and excellent environmental stability compared to pristine ZnO nanowalls, and the photoresponse exhibited a better linear relationship at 10 oC ~70 oC. The mechanism of UV photo sensing for the ZnO/Ag heterojunction was discussed. The results indicated that ZnO/Ag heterojunction could act as an interesting material for UV photodetectors with near-linear responses in outdoor temperatures.
关键词： ZnO/Ag heterostucture,near-liner,Ag nanorods,UV photodetectors,ZnO nanowalls
更新于2025-09-19 17:13:59
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High speed antimony-based superlattice photodetectors transferred on sapphire
摘要： We report the substrate transfer of InAs/GaSb/AlSb based type-II superlattice (T2SL) e-SWIR photodetector from native GaSb substrates to low-loss sapphire substrate in order to enhance the frequency response of the device. We have demonstrated the damage-free transfer of T2SL-based thin-films to sapphire substrate using top–down processing and a chemical epilayer release technique. After transfer the ?3 dB cut-off frequency increased from 6.4 GHz to 17.2 GHz, for 8 μm diameter circular mesas under ?15 V applied bias. We also investigated the cut-off frequency verses applied bias and lateral scaling to assess the limitations for even higher frequency performance.
关键词： high speed,photodetectors,substrate transfer,antimony-based superlattice,sapphire
更新于2025-09-19 17:13:59
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Thermo‐Phototronic‐Effect‐Enhanced Photodetectors Based on Porous ZnO Materials
摘要： Self-powered ultraviolet (UV) photodetectors with metal–semiconductor–metal (MSM) structure have attracted extensive attention due to their simple configuration and the fact that they require no external power source. However, the stability of Schottky-contact-based ultraviolet photodetectors is still poor due to the difficulty of controlling the surface states in the semiconductor, where it is almost impossible to obtain the same Schottky barrier heights in different devices. An Ohmic-contacted self-powered ultraviolet photodetector with an MSM structure is constructed by utilizing porous ZnO, which can dramatically increase photodetection performance due to its thermo-phototronic effect. The photocurrent signals of the photodetector at room temperature are 4.88 and 11.25 μA, which can be increased to 5.33 and 13.70 μA, respectively. The underlying physical mechanism of the performance enhancement is revealed through band-diagram analysis. This work extends the types of ZnO material-based photodetectors and holds great potential for developing high-performance self-powered ultraviolet photodetectors.
关键词： thermo-phototronic effect,photodetectors,thermopotential,self-powered electronics,porous ZnO
更新于2025-09-19 17:13:59
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In-Situ Tailoring of Vertically Coupled InAs p-i-p Quantum-Dot Infrared Photodetectors: Toward Homogeneous Dot Size Distribution and Minimization of Ina??Ga Intermixing
摘要： The authors report a detailed analysis of an epitaxial growth technique for Indium Arsenide (InAs) Quantum-dot infrared photodetectors to circumvent the detrimental effects arising from the progressively increasing dot-size in vertically coupled heterostructures. Constant overgrowth percentage of the vertically coupled dot-layers has been achieved with the implementation of the growth strategy, which has been validated by cross-sectional transmission electron microscopy (X-TEM) images of the samples. The optical characteristics of these samples have been analyzed through photoluminescence spectroscopy and photoluminescence excitation spectroscopy (PL and PLE) measurements which show longer wavelength response and reduced full width at half-maxima (FWHM) upon implementation of the growth strategy. X-TEM, in-plane and out-of-plane high resolution X-ray diffraction (HR-XRD) measurements suggest morphological improvement upon implementation of the growth strategy, with a reduction in the Indium desorption and lowering of defects and dislocation densities. Excellent correlation has been found between the different experimental results and also their theoretical simulations. The fabricated single-pixel photodetectors at low temperature (T=14K) show a broad response extending up to the MWIR region (~4.5μm) for one of the samples. Also, a strong spectral response in the SWIR region is obtained even at room temperature (T=300K). The highest responsivity (Rp) and specific detectivity (D*) values obtained are 166.17 A/W and 8.39 x 1010 cmHz1/2W-1 at a bias of 5V and 300K temperature.
关键词： p-i-p infrared photodetectors,InAs Quantum Dots,MBE growth strategy,homogenous dot size distribution,room temperature spectral response,In-Ga inter-diffusion
更新于2025-09-19 17:13:59
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Ultralong CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> nanowires synthesized by a ligand-assisted reprecipitation strategy for high-performance photodetectors
摘要： Organic-inorganic hybrid perovskite nanowires with well-defined structures have attracted considerable attention for optoelectronic applications. Perovskite nanowires integrated into practical optoelectronic devices are often hindered by the poor crystalline quality. Herein, a ligand-assisted reprecipitation strategy (LARP) is employed to prepare ultralong and freestanding CH3NH3PbI3 nanowires in large-scale. Oleylamine is adopted as an inhibitor, which can create a passivation layer on the surface of CH3NH3PbI3, to slow down the crystallization rate of CH3NH3PbI3 nanowire. With the low crystallization rate, several millimeters long and high-quality CH3NH3PbI3 nanowires with smooth surfaces can be synthesized in a large scale. Photodetectors fabricated on oleylamine assistant synthesized CH3NH3PbI3 nanowires exhibit high detectivity, which is five times higher than that of none oleylamine assistant synthesized CH3NH3PbI3 nanowires photoanode.
关键词： Organic-inorganic hybrid perovskite,photodetectors,nanowires,ligand-assisted reprecipitation strategy,optoelectronic applications,oleylamine
更新于2025-09-19 17:13:59
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Bio-inspired transparent MXene electrodes for flexible UV photodetectors
摘要： As a sort of rising two dimensional materials, MXenes have huge potential for they not only possess superb electrical conductivity and high hydrophilicity, but also enjoy mechanical strength and flexibility. Yet their applications to optoelectronics as electrodes are limited owing to the tradeoff between high transmittance and low conductive resistance, as a low resistance needs more conductive materials, reducing transmission by producing a larger surface coverage. To tackle this bottleneck, here a novel bio-inspired strategy is reported to acquire transparent flexible electrodes with both high transparency and high conductivity which outperform other transparent electrodes. It simultaneously exhibits reliable flexibility during a series of mechanical tests. All these properties of MXene electrodes result from well-designed hierarchical leaf vein network structure and strong adhesion between MXene and urea-treated substrates. In applications, a free-standing semi-transparent UV photodetector is constructed using the MXene electrodes, showing high-performance UV detection as well as superb flexibility and stability. The method provides a new route for MXene based optoelectronics.
关键词： bio-inspired design,MXene,UV photodetection,transparent electrodes,flexible photodetectors
更新于2025-09-19 17:13:59
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High charge carrier mobility in solution processed one-dimensional lead halide perovskite single crystals and their application as photodetectors
摘要： Organic inorganic hybrid metal halide perovskites have emerged as promising candidates for photovoltaics and light-emitting diodes. Recently, interest has been growing in the properties of low-dimensional metal halide perovskites, and one-dimensional versions with strong quantum confinement have demonstrated highly efficient broadband luminescence. Nevertheless, the charge transport mechanism in these low dimensional perovskites remains unclear. In this work, we characterised the charge mobility in one-dimensional perovskite single crystals using a space charge limited current method. Temperature dependent charge mobility measurements indicated that localized polarons at high temperature are replaced by delocalized polarons at low temperature with extended states in the polaronic band. A minimum mobility of 4.51 cm2/Vs was measured at room temperature. UV photodetectors based on these crystals show an ultrahigh photoresponsivity of 132.3 A W-1. These findings show the promise of high mobility low dimensional perovskite materials for optoelectronic applications.
关键词： space charge limited current,low-dimensional,charge transport,photodetectors,organic-inorganic hybrid metal halide perovskites
更新于2025-09-19 17:13:59