- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Near-infrared photodetection with plasmon-induced hot electrons using silicon nanopillar array structure
摘要： A plasmon-induced hot-electron photodetector based on silicon nanopillar array is developed. The nanostructure is fabricated by reactive ion etching with a monolayer of self-assembled polystyrene nanosphere in hexagonal close-packed lattice as the mask. Light absorption and hot-electron generation are mainly enhanced by the surface plasmon polaritons formed at the surface of the gold film on the nanopillar sidewalls. The photoresponse spans two telecom wavebands, viz. the range of 1250-1600 nm, and has a value of 2.5 mA/W at 1310 nm. The proposed silicon nanopillar-based hot-electron infrared detector has great potentials for device integration in silicon photonics relying on the economic large-area fabrication process.
关键词： near-infrared photodetector,Schottky diode,hot electrons,nanopillar
更新于2025-09-09 09:28:46
-
Optimizing electrospinning-hydrothermal hybrid process based on Taguchi method for modulation of point defects in ZnO micro/nano arrays towards photoelectronic application
摘要： Unlike previous work generally adopting high temperature annealing (≥500 ℃) to suppress defects in hydrothermal grown ZnO, this work suppressed ZnO defects by optimizing overall process parameters of low temperature electrospinning-hydrothermal hybrid process (≤300 ℃) with Taguchi method and Analysis of Variance (ANOVA). Sum ratio of defect peaks to eigen peaks (SRDE) in room-temperature photoluminescence (PL) spectrum was proposed to evaluate defect conditions in 27 experiments (L27 (38)). With the optimal process, good crystal quality (SRDE=0.31) was achieved at low temperature (200 ℃), of which the SRDE decreased by 68.04% compared with the initial counterpart. Then confirmation experiment was conducted to validate the selected levels, and results of signal-to-noise ratio (SNR) showed good agreement with the predicted ones. Besides, the response time and recovery time of the ZnO photodetectors with optimal process were decreased by 72.5% and 79.3%, respectively, compared with the initial ones. This method can also be used to fabricate ZnO materials with other wanted defect features.
关键词： Point defect,photodetector,ZnO micro/nano array,electrospinning-hydrothermal hybrid process,Taguchi method
更新于2025-09-09 09:28:46
-
Remote Evaluation of Rotational Velocity Using a Quadrant Photo-Detector and a DSC Algorithm
摘要： This paper presents an approach to remotely evaluate the rotational velocity of a measured object by using a quadrant photo-detector and a differential subtraction correlation (DSC) algorithm. The rotational velocity of a rotating object is determined by two temporal-delay numbers at the minima of two DSCs that are derived from the four output signals of the quadrant photo-detector, and the sign of the calculated rotational velocity directly represents the rotational direction. The DSC algorithm does not require any multiplication operations. Experimental calculations were performed to confirm the proposed evaluation method. The calculated rotational velocity, including its amplitude and direction, showed good agreement with the given one, which had an amplitude error of ~0.3%, and had over 1100 times the efficiency of the traditional cross-correlation method in the case of data number N > 4800. The confirmations have shown that the remote evaluation of rotational velocity can be done without any circular division disk, and that it has much fewer error sources, making it simple, accurate and effective for remotely evaluating rotational velocity.
关键词： rotational velocity,remote evaluation,differential subtraction correlation,quadrant photodetector,temporal-delay number
更新于2025-09-09 09:28:46
-
Graphene interdigital electrodes for improving sensitivity in Ga2O3:Zn deep-ultraviolet photoconductive detector
摘要： Graphene (Gr) has been widely used as a transparent electrode material for photodetectors due to its high conductivity and high transmittance, in recent years. However, the currently low-efficiency manipulation of Gr has hindered the arraying and practical use of such detectors. We invented a multi-step method of accurately tailoring graphene into interdigital electrodes, for fabricating a sensitive, stable deep-ultraviolet photodetector based on Zn-doped Ga2O3 films. The fabricated photodetector exhibits a series of excellent performance, including extremely low dark current (~10-11 A), ultra-high photo-to-dark ratio (>105), satisfactory responsivity (1.05 A/W) and excellent selectivity for DUV band, compared to those with ordinary metal electrodes. The raising of photocurrent and responsivity is attributed to the increase of incident photons through Gr, and separated carriers caused by the built-in electric field formed at the interface of Gr and Ga2O3:Zn films. The proposed ideas and methods of tailoring Gr can not only improve the performance of devices, but more importantly, it contributes to the practical development of graphene.
关键词： gallium oxide,photodetector,deep ultraviolet,graphene interdigital electrodes,ultralow dark current
更新于2025-09-09 09:28:46
-
2D-Layer-Dependent Behavior in Lateral Au/WS <sub/>2</sub> /Graphene Photodiode Devices with Optical Modulation of Schottky Barriers
摘要： We investigate the 2D-layer-dependent electronic and optoelectronic properties of lateral Au/graphene/WS2 photodetecting diodes. All 2D materials used [graphene and WS2 domains [monolayer (1L) and bilayer (2L)] were grown by chemical vapor deposition, which is promising for the lateral scalable applications. The output current of asymmetric photodetectors showed clear rectification because of the different Schottky barrier heights between the Au/WS2 and WS2/Gr interfaces. Electrostatic gating and laser illumination are demonstrated to tune the rectifying behavior, as a result of modulated Schottky barriers. Especially, the channel current can be switched on by laser irradiation from an initial off state when negatively biased. This is attributed to a decreased Au/WS2 barrier height as photogenerated holes accumulated at the Au/WS2 interface and increased the electron affinity of WS2. As a photodetector, an on?off ratio of about 200 can be achieved under a laser intensity of 2.7 × 105 mW/cm2. A greater-than-unity photogain is measured for all devices, indicating that the photocurrent is mainly driven by changes to the Schottky barrier heights and corresponding changes in thermionic emission rather than a photovoltaic effect. The layer-dependent conductivity and photoresponsivity are due to the different electron affinities and band gaps of 1L and 2L WS2. Devices based on 2L WS2 show much-improved conductivity and photoresponsivity compared to those based on 1L WS2.
关键词： photodetector,WS2,graphene,heterostructures,rectification,2D materials
更新于2025-09-09 09:28:46
-
Comprehensive Pyro‐Phototronic Effect Enhanced Ultraviolet Detector with ZnO/Ag Schottky Junction
摘要： As a coupling effect of pyroelectric and photoelectric effect, pyro-phototronic effect has demonstrated an excellent tuning role for fast response p–n junction photodetectors (PDs). Here, a comprehensive pyro-phototronic effect is utilized to design and fabricate a self-powered and flexible ultraviolet PD based on the ZnO/Ag Schottky junction. By using the primary pyroelectric effect, the maximal transient photoresponsivity of the self-powered PDs can reach up to 1.25 mA W?1 for 325 nm illumination, which is improved by 1465% relative to that obtained from the steady-state signal. The relative persistent secondary pyroelectric effect weakens the height of Schottky barrier, leading to a reduction of the steady-state photocurrent with an increase in the power density. When the power density is large enough, the steady-state photocurrent turns into a reverse direction. The corresponding tuning mechanisms of the comprehensive pyro-phototronic effect on transient and steady-state photocurrent are revealed based on the bandgap diagrams. The results may help us to further clarify the mechanism of the pyro-phototronic effect on the photocurrent and also provide a potential way to optimize the performance of self-powered PDs.
关键词： ultraviolet photodetector,Schottky junction,secondary pyroelectric effect,pyro-phototronic effect,self-powered
更新于2025-09-04 15:30:14
-
Wet-Chemical Synthesis of Surface-Passivated Halide Perovskite Microwires for Improved Optoelectronic Performance and Stability
摘要： One-dimensional (1D) halide perovskite materials with intrinsic high carrier mobility and long diffusion length hold great promises for high-performance optoelectronic devices, in which the passivation of the surface defects is of significance for further boosting its optoelectronic performance as well as its moisture stability. Herein, we demonstrate a simple room-temperature wet-chemical synthetic protocol for perovskite microwires with controlled morphologies and passivated surface states. This strategy allows for facile assembly of hydrophobic 1H,1H-perfluorooctylamine (PFA) molecules on the surface of the perovskite microwires owing to the coordination binding between the amino groups of PFA and Pb2+. Both steady and time-resolved photoluminescence measurements revealed that the passivation of PFA greatly benefit for the inhibition of the photogenerated carriers recombination. The constructed perovskite microwire-based photodetectors have shown increased detectivity of 4.99 × 1011 jones and responsivity of 1.27 A/W (light power density of 1 mW/cm2). Moreover, the hydrophobic fluorocarbon alkyl chains endow the perovskite microwires with higher resistance toward moisture. Such coating of a water-resisting layer resulted in greatly enhanced stability of perovskite microwires under the humidity of 55 ± 5% over 30 days. We thus believe that our work is of importance for the development of 1D halide perovskite photodetectors with highly improved performance and stability.
关键词： stability,surface passivation,perovskite microwires,photodetector,PFA
更新于2025-09-04 15:30:14
-
Long Wavelength Infrared Quantum Cascade Detector
摘要： The effect of the barrier width in the photovoltaic-type quantum cascade detector structure on the responsivity and the zero-bias resistance of the device are opposite. A wide barrier can increase the zero-bias resistance but hinder the transport of photo-generated carriers and decrease the responsivity. The design of a long wave infrared cascade detector usually focuses on increasing the zero bias resistance by using wide barriers to lower the thermal noise, but the photocurrent might be low in this case. Even though the thermal noise that dominates the noise performance of a photovoltaic quantum cascade detector is very low, it is possible that effective photoresponse signals cannot be obtained when the photocurrent is as low as the noise current of measurement circuits, which might be higher than the thermal noise of the detector itself. In this work, we modified the structure of our previous long wavelength infrared quantum cascade detector by increasing the number of cascaded stages, while reducing the barrier thickness to improve the responsivity of the device. Although the device’s zero bias resistance decreases due to thinning of the barrier, the detectivity is almost unaffected due to the significant increase in response. More importantly, the operating temperature of the device is increased. Therefore, optimization of long wave infrared QCDs should consider both the resistance and the photocurrent flow.
关键词： Quantum Cascade Photodetector,Long Wavelength Infrared
更新于2025-09-04 15:30:14
-
Optoelectronic and photocatalytic properties of zinc sulfide nanowires synthesized by vapor-liquid-solid process
摘要： Zinc sul?de (ZnS) is a wide band-gap semiconductor with excellent optoelectronic properties suitable for photo-sensing devices and photocatalysts. Herein, the ZnS nanowires (ZnS NWs) have been successfully synthesized using thermal evaporation based on vapor-liquid-solid (VLS) method. From the examinations of photosensing device under ultraviolet B (UVB) irradiation, the photocurrent gain (Pg), responsivity (Rλ), response time and recovery time are 0.572, 2.761 mW/cm2, 3.2 s and 3.6 s, respectively. As to photocatalytic activity for methylene blue (MB), the apparent rate coe?cient (K) of ZnS NWs is 9.78 × 10?3 (min?1). Although ZnS NWs-based photodetector cannot be workable under ultraviolet A (UVA) irradiation, with referring to recent medical literatures, UVB radiation is the major environmental risk factor for developing human skin cancer, the most common cancer worldwide. Thus, the most important contribution in this work is that the ZnS NWs-based UVB radiation-oriented photodetector has been successfully demonstrated via a simple process.
关键词： Photodetector,Zinc sul?de nanowires (ZnS NWs),Photocurrent gain (Pg),Optoelectronic,Vapor-liquid-solid (VLS),Apparent rate coe?cient (K),Responsivity (Rλ),Ultraviolet B (UVB) irradiation
更新于2025-09-04 15:30:14
-
InAs/InAsSb Type-II Superlattice Mid-Wavelength Infrared Focal Plane Array With Significantly Higher Operating Temperature Than InSb
摘要： We report focal plane array (FPA) results on a mid-wavelength InAs/InAsSb type-II strained layer superlattice (T2SLS) unipolar barrier infrared detector with a cutoff wavelength of 5.4 μm. For 300 K background in the 3–5-μm band, f/2 aperture, an FPA operating at 150 K exhibits a mean noise equivalent differential temperature (NEDT) of 18.5 mK, and an NEDT operability of 99.7%. The NE(cid:2)T distribution has a width of 8 mK, with no noticeable distribution tail, indicating excellent uniformity. The mean noise-equivalent irradiance is 9.1 × 1011 photons/sec-cm2. The mean quantum ef?ciency is 49.1% without antire?ection coating, and the mean speci?c detectivity (D?) is 2.53 × 1011 cm-Hz?/W. Bene?tting from an absorber material with a much longer Shockley–Read–Hall minority carrier lifetime, and a device architecture that suppresses generation-recombination and surface-leakage dark current, the InAs/InAsSb T2SLS barrier infrared detector FPA has demonstrated a signi?cantly higher operating temperature than the mid-wavelength infrared market-leading InSb.
关键词： Infrared detector,heterostructure,InAs/InAsSb,type-II superlattice,photodetector,nBn,unipolar barrier,focal plane array
更新于2025-09-04 15:30:14