Mid-wavelength infrared(MWIR)and long-wavelength infrared(LWIR)detectors,which operate within the 3-14µm wavelength range,have been extensively employed in various fields,including military,space exploration,envi...Mid-wavelength infrared(MWIR)and long-wavelength infrared(LWIR)detectors,which operate within the 3-14µm wavelength range,have been extensively employed in various fields,including military,space exploration,environmental monitoring,biomedicine,and chemical analysis.While thermal detectors are commonly used,their limitations in sensitivity and response time render them less suitable for next-generation MWIR and LWIR applications.These advanced applications necessitate the use of narrow bandgap semiconductor-based photodetectors,which offer tunable optoelectronic properties and higher specific detectivity compared to thermal detectors.In this review,we provide a detailed analysis of the operational principles and manufacturing strategies of infrared photodetectors based on narrow bandgap semiconductors,which enable high-performance detection in the MWIR and LWIR regions.Our focus is specifically on scalable fabrication of MWIR and LWIR photodetectors,emphasizing devices with active areas ranging from millimeters to centimeters.Researches on large-scale fabrication of infrared photodetectors using quantum dots,two-dimensional(2D)van der Waals(vdW)materials,and three-dimensional(3D)bulk semiconductors are investigated.Finally,we summarize the remaining challenges in developing scalable narrow bandgap semiconductor-based MWIR and LWIR photodetectors for commercialization.By addressing the obstacles such as the difficulty in large-scale unform film synthesis,the requirement for cryogenic device operation,and the introduction of high-density of defect states during the hybridization processes,MWIR and LWIR photodetectors based on narrow bandgap semiconductors will pave the way for designing new sensory systems and applications in a wavelength regime that has been less developed compared to the visible and near-infrared(NIR)ranges.展开更多
Photodetectors can convert light energy into electrical signals,so are widely used in photovoltaics,photon counting,monitoring,and imaging.Photodetectors are easy to prepare high-resolution photochips because of their...Photodetectors can convert light energy into electrical signals,so are widely used in photovoltaics,photon counting,monitoring,and imaging.Photodetectors are easy to prepare high-resolution photochips because of their small size unit integration.However,these photodetector units often exhibit poor photoelectric performance due to material defects and inadequate structures,which greatly limit the functions of devices.Designing modification strategies and micro-/nanostructures can compensate for defects,adjust the bandgap,and develop novel quantum structures,which consequently optimize photovoltaic units and revolutionize optoelectronic devices.Here,this paper aims to comprehensively elaborate on the surface/interface engineering scheme of micro-/nano-photodetectors.It starts from the fundamentals of photodetectors,such as principles,types,and parameters,and describes the influence of material selection,manufacturing techniques,and post-processing.Then,we analyse in detail the great influence of surface/interface engineering on the performance of photovoltaic devices,including surface/interface modification and micro-/nanostructural design.Finally,the applications and prospects of optoelectronic devices in various fields such as miniaturization of electronic devices,robotics,and human–computer interaction are shown.展开更多
UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite.However,the underlying mechanisms conc...UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite.However,the underlying mechanisms concerning UV absorption,defect passivation,and efficacy optimization of these additives remain unresolved.Herein,two UV tautomeric absorbers(UV320 and UV327)are selected as defect-passivators for perovskites.The keto-enol tautomeric evolution processes and corresponding defect passivation performance/mechanism of both the original molecules and their tautomers are thoroughly compared and elucidated through experimental characterizations and density functional theory calculations.The additional carbonyl(-C=O)groups generated through the keto-enol tautomeric process triggered by the Cl atom in UV327 ultimately provide superior chemical coordination and enhanced defect-passivation capability compared to the original counterparts.Moreover,the versatility of K-UV327 is further demonstrated by its optimization of SnO_(2)film quality,interfacial energy band alignment,charge extraction efficiency,and defect state suppression.The photodetector optimized by UV327's tautomer achieves an ultralow dark current density of 3.22×10^(-10)A cm^(-2),an enhanced linear dynamic range of 94.14 d B,and a fast response time of 23.35/26.19μs.Notably,unencapsulated devices maintain a stable response at 3900 Hz following 300 h exposure to 40%±5%relative humidity and 30 h UV irradiation.展开更多
Solar-blind ultraviolet photodetectors(UV PDs),capable of detecting UV radiation without interference from sun-light,have attracted significant interest.Herein,we propose a 0D/1D heterostructure for UV PDs,which was f...Solar-blind ultraviolet photodetectors(UV PDs),capable of detecting UV radiation without interference from sun-light,have attracted significant interest.Herein,we propose a 0D/1D heterostructure for UV PDs,which was fabricated by spin-coating MoS_(2)quantum dots onto p-AlGaN nanowires.The device achieves a high responsivity of 175.5 mA/W and a fast response speed of 83 ms at 250 nm illumination under self-powered mode,which improved nearly 1235%and 521%after MoS_(2)decoration,respectively.These improvements can be attributed to the type-Ⅱheterostructure formed between p-AlGaN and MoS_(2),which facilitates enhanced charge separation and carrier transport.Later,we demonstrate the implementation of this device in optical communication,achieving high-accuracy transmission of"GaN"ASCII code signals.Such a 0D/1D het-erostructure provides an effective strategy for high-performance solar-blind UV PD.展开更多
Infrared and terahertz waves constitute pivotal bands within the electromagnetic spectrum,distinguished by their robust penetration capabilities and non-ionizing nature.These wavebands offer the potential for achievin...Infrared and terahertz waves constitute pivotal bands within the electromagnetic spectrum,distinguished by their robust penetration capabilities and non-ionizing nature.These wavebands offer the potential for achieving high-resolution and non-destructive detection methodologies,thereby possessing considerable research significance across diverse domains including communication technologies,biomedical applications,and security screening systems.Two-dimensional materials,owing to their distinctive optoelectronic attributes,have found widespread application in photodetection endeavors.Nonetheless,their efficacy diminishes when tasked with detecting lower photon energies.Furthermore,as the landscape of device integration evolves,two-dimensional materials struggle to align with the stringent demands for device superior performance.Topological materials,with their topologically protected electronic states and non-trivial topological invariants,exhibit quantum anomalous Hall effects and ultra-high carrier mobility,providing a new approach for seeking photosensitive materials for infrared and terahertz photodetectors.This article introduces various types of topological materials and their properties,followed by an explanation of the detection mechanism and performance parameters of photodetectors.Finally,it summarizes the current research status of near-infrared to far-infrared photodetectors and terahertz photodetectors based on topological materials,discussing the challenges faced and future prospects in their development.展开更多
The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(...The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(PDs)due to their unique optoelectronic properties and flexible synthesis routes.This review explores the approaches used in the development and use of optoelectronic devices made of different nanoscale perovskite architectures,including quantum dots,nanosheets,nanorods,nanowires,and nanocrystals.Through a thorough analysis of recent literature,the review also addresses common issues like the mechanisms underlying the degradation of perovskite PDs and offers perspectives on potential solutions to improve stability and scalability that impede widespread implementation.In addition,it highlights that photodetection encompasses the detection of light fields in dimensions other than light intensity and suggests potential avenues for future research to overcome these obstacles and fully realize the potential of nanoscale perovskite materials in state-of-the-art photodetection systems.This review provides a comprehensive overview of nanoscale perovskite PDs and guides future research efforts towards improved performance and wider applicability,making it a valuable resource for researchers.展开更多
Quantum dot(QD)-based infrared photodetector is a promising technology that can implement current monitoring,imaging and optical communication in the infrared region. However, the photodetection performance of self-po...Quantum dot(QD)-based infrared photodetector is a promising technology that can implement current monitoring,imaging and optical communication in the infrared region. However, the photodetection performance of self-powered QD devices is still limited by their unfavorable charge carrier dynamics due to their intrinsically discrete charge carrier transport process. Herein, we strategically constructed semiconducting matrix in QD film to achieve efficient charge transfer and extraction.The p-type semiconducting CuSCN was selected as energy-aligned matrix to match the n-type colloidal PbS QDs that was used as proof-of-concept. Note that the PbS QD/CuSCN matrix not only enables efficient charge carrier separation and transfer at nano-interfaces but also provides continuous charge carrier transport pathways that are different from the hoping process in neat QD film, resulting in improved charge mobility and derived collection efficiency. As a result, the target structure delivers high specific detectivity of 4.38 × 10^(12)Jones and responsivity of 782 mA/W at 808 nm, which is superior than that of the PbS QD-only photodetector(4.66 × 10^(11)Jones and 338 mA/W). This work provides a new structure candidate for efficient colloidal QD based optoelectronic devices.展开更多
A polarization-sensitive and flexible photodetector was fabricated through the precise alignment of perovskite nanowires(NWs)using a brush coating technique.The alignment of the NWs was meticulously examined,consideri...A polarization-sensitive and flexible photodetector was fabricated through the precise alignment of perovskite nanowires(NWs)using a brush coating technique.The alignment of the NWs was meticulously examined,considering various chemical properties of the solvent,such as boiling point,viscosity,and surface tension.Notably,when the NWs were brush-coated with toluene dispersion,the NWs were aligned in higher order than those processed from octane dispersion.The degree of alignment was correlated with the photodetector property.Especially,the well-aligned NW photodetector exhibited a two-fold disparity in current response contingent on the polarization direction.Furthermore,even after enduring 500 bending cycles,the device retained 80%of its photodetector performance.This approach underscores the potential of solution-processed flexible photodetectors for advanced optical applications under dynamic operating conditions.展开更多
Flexible wearable optoelectronic devices fabricated fromorganic–inorganic hybrid perovskites significantly accelerate the developmentof portable energy,biomedicine,and sensing fields,but their poor thermal stabilityh...Flexible wearable optoelectronic devices fabricated fromorganic–inorganic hybrid perovskites significantly accelerate the developmentof portable energy,biomedicine,and sensing fields,but their poor thermal stabilityhinders further applications.Conversely,all-inorganic perovskites possessexcellent thermal stability,but black-phase all-inorganic perovskite filmusually requires high-temperature annealing steps,which increases energy consumptionand is not conducive to the fabrication of flexible wearable devices.In this work,an unprecedented low-temperature fabrication of stable blackphaseCsPbI3perovskite films is demonstrated by the in situ hydrolysis reactionof diphenylphosphinic chloride additive.The released diphenyl phosphateand chloride ions during the hydrolysis reaction significantly lower the phasetransition temperature and effectively passivate the defects in the perovskitefilms,yielding high-performance photodetectors with a responsivity of 42.1 AW−1 and a detectivity of 1.3×10^(14)Jones.Furthermore,high-fidelity imageand photoplethysmography sensors are demonstrated based on the fabricated flexible wearable photodetectors.This work provides a newperspective for the low-temperature fabrication of large-area all-inorganic perovskite flexible optoelectronic devices.展开更多
Tin-lead(Sn-Pb)mixed perovskites are extensively investigated in near-infrared(NIR)photodetectors(PDs)owing to their excellent photoelectric performance.However,achieving high-performance Sn-Pb mixed PDs remains chall...Tin-lead(Sn-Pb)mixed perovskites are extensively investigated in near-infrared(NIR)photodetectors(PDs)owing to their excellent photoelectric performance.However,achieving high-performance Sn-Pb mixed PDs remains challenging,primarily because of the rapid crystallization and the susceptibility of Sn^(2+) to oxidation.To ad⁃dress these issues,this study introduces the multifunctional molecules 2,3-difluorobenzenamine(DBM)to modulate the crystallization of Sn-Pb mixed perovskites and retard the oxidation of Sn^(2+),thereby significantly enhancing film quality.Compared with the pristine film,Sn-Pb mixed perovskite films modulated by DBM molecules exhibit a high⁃ly homogeneous morphology,reduced roughness and defect density.The self-powered NIR PDs fabricated with the improved films have a spectral response range from 300 nm to 1100 nm,a peak responsivity of 0.51 A·W^(-1),a spe⁃cific detectivity as high as 2.46×10^(11)Jones within the NIR region(780 nm to 1100 nm),a linear dynamic range ex⁃ceeding 152 dB,and ultrafast rise/fall time of 123/464 ns.Thanks to the outstanding performance of PDs,the fabri⁃cated 5×5 PDs array demonstrates superior imaging ability in the NIR region up to 980 nm.This work advances the development of Sn-Pb mixed perovskites for NIR detection and paves the way for their commercialization.展开更多
This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system ci...This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system circuit is designed and fabricated,enabling the detection,acquisition,and calibration of weak solar-blind UV signals.Experimental results demonstrate that under zero bias conditions,with a UV light power density of 3.45μW/cm^(2) at 260 nm,the sample achieves a peak responsivity(R)of 0.085 A·W^(−1),an external quantum efficiency(EQE)of 40.7%,and a detectivity(D^(*))of 7.46×10^(12) cm·Hz^(1/2)·W^(−1).The system exhibits a bandpass characteristic within the 240–280 nm wavelength range,coupled with a high signal-to-noise ratio(SNR)of 39.74 dB.展开更多
Pulsed-laser deposition has been developed to prepare large-area In_(2)S_(3)nanofilms and their photoelectric characteristics have been investigated.The In_(2)S_(3)nanofilm grown under 500℃is highly oriented along th...Pulsed-laser deposition has been developed to prepare large-area In_(2)S_(3)nanofilms and their photoelectric characteristics have been investigated.The In_(2)S_(3)nanofilm grown under 500℃is highly oriented along the(103)direction with exceptional crystallinity.The corresponding(103)-oriented In_(2)S_(3)photodetectors exhibit broadband photoresponse from 370.6 nm to 1064 nm.Under 635 nm illumination,the optimized responsivity,external quantum efficiency,and detectivity reach 19.8 A/W,3869%,and 2.59×10^(12)Jones,respectively.In addition,the device exhibits short rise/decay time of 3.9/3.0 ms.Of note,first-principles calculations have unveiled that the effective carrier mass along the(103)lattice plane is much smaller than those along the(100),(110)and(111)lattice planes,which thereby enables high-efficiency transport of photocarriers and thereby the excellent photosensitivity.Profited from the sizable bandgap,the In_(2)S_(3)photodetectors also showcase strong robustness against elevated operating temperature.In the end,proof-of-concept imaging application beyond human vision and under high operating temperature as well as heart rate monitoring have been achieved by using the In_(2)S_(3)device of the sensing component.This study introduces a novel crystal orientation engineering paradigm for the implementation of next-generation advanced optoelectronic systems.展开更多
The rise of smart wearable devices has driven the demand for flexible,high-performance optoelectronic devices with low power and easy high-density integration.Emerging Two-dimensional(2D)materials offer promising solu...The rise of smart wearable devices has driven the demand for flexible,high-performance optoelectronic devices with low power and easy high-density integration.Emerging Two-dimensional(2D)materials offer promising solutions.However,the use of 3D metal in traditional 2D devices often leads to Fermi-level pinning,compromising device performance.2D metallic materials,such as graphene and 2H-phase NbSe_(2),present a new avenue for addressing this issue and constructing high-performance,low-power photodetectors.In this work,we designed an all-2D asymmetric contacts photodetector using Gr and NbSe_(2)as electrodes for the 2D semiconductor WSe_(2).The asymmetric Schottky barriers and built-in electric fields facilitated by this architecture resulted in outstanding photovoltaic characteristics and self-powered photodetection.Under zero bias,the device exhibited a responsivity of 287 mA/W,a specific detectivity of 5.3×10^(11)Jones,and an external quantum efficiency of 88%.It also demonstrated an ultra-high light on/offratio(1.8×10^(5)),ultra-fast photoresponse speeds(80/72μs),broad-spectrum responsiveness(405980 nm),and exceptional cycling stability.The applications of the Gr/WSe_(2)/NbSe_(2)heterojunction in imaging and infrared optical communication have been explored,underscoring its significant potential.This work offers an idea to construct all-2D ultrathin optoelectronic devices.展开更多
It is regretful that the data error due to the large number of samples tested.The correct data and figure should be as follows:This correction have no impact on the remainder of the manuscript,the interpretation of th...It is regretful that the data error due to the large number of samples tested.The correct data and figure should be as follows:This correction have no impact on the remainder of the manuscript,the interpretation of the data,or the conclusions reached.The authors would like to apologize for any inconvenience caused.展开更多
Wearable photodetectors have come under the limelight of optoelectronic technologies on account of multiple advantages spanning light weight,easy-portability,excellent bendability,outstanding conformability,etc.Among ...Wearable photodetectors have come under the limelight of optoelectronic technologies on account of multiple advantages spanning light weight,easy-portability,excellent bendability,outstanding conformability,etc.Among diverse candidate materials,low-dimensional van der Waals materials(LDvdWMs)have emerged to be preeminent owing to the dangling-bond-free surface,exceptional carrier mobility,nanoscale dimensionality,and excellent light-harvesting capability.However,to date,the majority of flexible LDvdWM photodetectors have been fabricated through exfoliation-,transfer-,or solution-processing methods,which are plagued by limitations such as low production yield,inadequate photosensitivity,and sluggish response rate.Thus far,constructing LDvdWM photodetectors in situ on flexible substrates remains quite challenging due to the irreconcilable contradiction between the weak robustness of flexible polymer substrates against high temperature and the large thermal budget required for crystallization.This study develops scalable preparation of Sb_(2)Se_(3)nanofilm directly on flexible polyimide substrates by exploiting pulsed-laser deposition(PLD),where highly energetic species can be generated to enable overcoming the reaction barrier for crystallization at a relatively low temperature.The corresponding Sb_(2)Se_(3)photodetectors have exhibited high responsivity of 1.15 A/W,exceptional external quantum efficiency of 269%,and impressive specific detectivity reaching 2.4×10^(11)Jones,coupled with swift switching characteristics.Importantly,excellent durability to repeated bending treatments has been confirmed by the consistent photoresponse over 500 convex/concave bending cycles.Furthermore,the device has showcased strong robustness against extrinsic impinging.In the end,by using Sb_(2)Se_(3)photodetectors as sensing components,wide-band imaging beyond human vision and heart rate monitoring have been realized.This study has underscored the high efficacy of PLD for reconciling the long-standing contradiction between the weak robustness of flexible polymer substrates against high temperature and the substantial thermal energy required for crystallization,opening new opportunities towards next-generation wearable optoelectronic industry.展开更多
Planar-structured amorphous InGaZnO(a-IGZO)film-based UV photodetectors with different ITO interdigitated electrode spacings were developed on flexible PI substrates via radio frequency magnetron sputtering and non-li...Planar-structured amorphous InGaZnO(a-IGZO)film-based UV photodetectors with different ITO interdigitated electrode spacings were developed on flexible PI substrates via radio frequency magnetron sputtering and non-lithographic fabrication processes.The effects of oxygen flow rate on the surface morphology,electrical transport,and chemical bonding properties of the a-IGZO films were systematically investigated to optimize the performance of the flexible detector.The average transmittance of the flexible a-IGZO photodetector is over 90%in the visible spectral range with a large photo-to-dark current ratio of 3.9×10^(3)under 360 nm UV illumination.The photocurrent of the detectors increases with decreasing the electrode spacing,which is attribute to formation of higher electrical field and drifting more electron-hole pairs to the electrode with shortening the electrode spacing.Under a UV illumination intensity of 9.1 mW/cm~2,the highest responsivity and detectivity of the photodetector with the electrode spacing of 0.4 mm reach 62.1 mA/W and2.83×10^(11)cm·Hz^(1/2)·W^(-1)at 11 V bias voltage,respectively.The flexible detector exhibits enhanced photoresponse performance with the rise and decay time of 2.02 and 0.94 s,respectively.These results can be used in a practical scheme to design and realize the a-IGZO based UV photodetectors with excellent transparency and flexibility for wearable UV monitoring applications.展开更多
Graphene has garnered significant attention in photodetection due to its exceptional optical,electrical,mechanical,and thermal properties.However,the practical application of two-dimensional(2D)graphene in optoelectro...Graphene has garnered significant attention in photodetection due to its exceptional optical,electrical,mechanical,and thermal properties.However,the practical application of two-dimensional(2D)graphene in optoelectronic fields is limited by its weak light absorption(only 2.3%)and zero bandgap characteristics.Increasing light absorption is a critical scientific challenge for developing high-performance graphene-based photodetectors.Three-dimensional(3D)graphene comprises vertically grown stacked 2D-graphene layers and features a distinctive porous structure.Unlike 2D-graphene,3D-graphene offers a larger specific surface area,improved electrochemical activity,and high chemical stability,making it a promising material for optoelectronic detection.Importantly,3D-graphene has an optical microcavity structure that enhances light absorption through interaction with incoming light.This paper systematically reviews and analyzes the current research status and challenges of 3D-graphene-based photodetectors,aiming to explore feasible development paths for these devices and promote their industrial application.展开更多
Two-dimensional(2D)noble transition-metal dichalcogenide materials(NTMDs)have garnered remarkable attention due to their intriguing properties exhibiting potential applications in nanoelectronics,optoelectronics,and p...Two-dimensional(2D)noble transition-metal dichalcogenide materials(NTMDs)have garnered remarkable attention due to their intriguing properties exhibiting potential applications in nanoelectronics,optoelectronics,and photonics.The electronic structure and physical properties of 2D NTMDs can be effectively modulated using alloy engineering strategy.Nevertheless,the precise growth of wafer-scale 2D NTMDs alloys remains a significant challenge.In this work,we have achieved the controllable preparation of wafer-scale(2-inch)2D PdS_(2x)Se_(2(1-x)) nanofilms(NFs)with fully tunable compositions on various substrates using pre-deposited Pd NFs assisted chemical vapor deposition technique.High-performance photodetectors based on the PdS_(2x)Se_(2(1-x))NFs were fabricated,which exhibit broadband photodetection performance from visible to near-infrared(NIR)wavelength range at room temperature.Significantly,the PdS0.9Se1.1-based photodetectors display a responsivity up to 0.192 A W^(-1) and a large specific detectivity of 5.5×1011 Jones for 850 nm light,enabling an excellent high-resolution NIR single-pixel imaging(SPI)without an additional filtering circuit.Our work paves a new route for the controlled synthesis of wafer-scale and high-quality 2D NTMDs alloy NFs,which is essential for designing advanced optoelectronic devices.展开更多
Correction to:Opto-Electronic Science https://www.oejournal.org/oes/article/doi/10.29026/oes.2024.230029 published online 21 March 2024.After the publication of this article1,it was brought to our attention that the i...Correction to:Opto-Electronic Science https://www.oejournal.org/oes/article/doi/10.29026/oes.2024.230029 published online 21 March 2024.After the publication of this article1,it was brought to our attention that the inset image and absorption spectrum in Fig.1(b)contained a mistake,probably leading to misunderstandings.The inset image and the absorption spectrum in Fig.1(b)were not based on the specific batch of PbS colloidal quantum dots(CQDs)used in this work.展开更多
Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating el...Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating electron injection at the emitter to investigate the carrier dynamics time and impedance spectroscopy in GaAs/AlGaAs QWIPs. Our findings provide novel evidence that the escape time of electrons is the key limiting factor for the 3-dB bandwidth of QWIPs. Moreover, to characterize the impact of carrier dynamics time and non-equilibrium space charge region on impedance, we developed an equivalent circuit model where depletion region resistance and capacitance are employed to describe non-equilibrium space charge region. Using this model, we discovered that under illumination, both net charge accumulation caused by variations in carrier dynamics times within quantum wells and changes in width of non-equilibrium space charge region exert different dominant influences on depletion region capacitance at various doping concentrations.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.2022R1C1C100923512)by the Yonsei University Research Fund of 2023-22-0076supported by the POSCO Science Fellowship from POSCO TJ Park Foundation。
文摘Mid-wavelength infrared(MWIR)and long-wavelength infrared(LWIR)detectors,which operate within the 3-14µm wavelength range,have been extensively employed in various fields,including military,space exploration,environmental monitoring,biomedicine,and chemical analysis.While thermal detectors are commonly used,their limitations in sensitivity and response time render them less suitable for next-generation MWIR and LWIR applications.These advanced applications necessitate the use of narrow bandgap semiconductor-based photodetectors,which offer tunable optoelectronic properties and higher specific detectivity compared to thermal detectors.In this review,we provide a detailed analysis of the operational principles and manufacturing strategies of infrared photodetectors based on narrow bandgap semiconductors,which enable high-performance detection in the MWIR and LWIR regions.Our focus is specifically on scalable fabrication of MWIR and LWIR photodetectors,emphasizing devices with active areas ranging from millimeters to centimeters.Researches on large-scale fabrication of infrared photodetectors using quantum dots,two-dimensional(2D)van der Waals(vdW)materials,and three-dimensional(3D)bulk semiconductors are investigated.Finally,we summarize the remaining challenges in developing scalable narrow bandgap semiconductor-based MWIR and LWIR photodetectors for commercialization.By addressing the obstacles such as the difficulty in large-scale unform film synthesis,the requirement for cryogenic device operation,and the introduction of high-density of defect states during the hybridization processes,MWIR and LWIR photodetectors based on narrow bandgap semiconductors will pave the way for designing new sensory systems and applications in a wavelength regime that has been less developed compared to the visible and near-infrared(NIR)ranges.
文摘Photodetectors can convert light energy into electrical signals,so are widely used in photovoltaics,photon counting,monitoring,and imaging.Photodetectors are easy to prepare high-resolution photochips because of their small size unit integration.However,these photodetector units often exhibit poor photoelectric performance due to material defects and inadequate structures,which greatly limit the functions of devices.Designing modification strategies and micro-/nanostructures can compensate for defects,adjust the bandgap,and develop novel quantum structures,which consequently optimize photovoltaic units and revolutionize optoelectronic devices.Here,this paper aims to comprehensively elaborate on the surface/interface engineering scheme of micro-/nano-photodetectors.It starts from the fundamentals of photodetectors,such as principles,types,and parameters,and describes the influence of material selection,manufacturing techniques,and post-processing.Then,we analyse in detail the great influence of surface/interface engineering on the performance of photovoltaic devices,including surface/interface modification and micro-/nanostructural design.Finally,the applications and prospects of optoelectronic devices in various fields such as miniaturization of electronic devices,robotics,and human–computer interaction are shown.
基金the financial support from Xingdian Creative Industry Talent Project of Yunnan Province(No.XDYC-CYCX-2024-0025)Science and Technology Special Projects of Southwest United Graduate School and Innovative Team of Yunnan Province。
文摘UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite.However,the underlying mechanisms concerning UV absorption,defect passivation,and efficacy optimization of these additives remain unresolved.Herein,two UV tautomeric absorbers(UV320 and UV327)are selected as defect-passivators for perovskites.The keto-enol tautomeric evolution processes and corresponding defect passivation performance/mechanism of both the original molecules and their tautomers are thoroughly compared and elucidated through experimental characterizations and density functional theory calculations.The additional carbonyl(-C=O)groups generated through the keto-enol tautomeric process triggered by the Cl atom in UV327 ultimately provide superior chemical coordination and enhanced defect-passivation capability compared to the original counterparts.Moreover,the versatility of K-UV327 is further demonstrated by its optimization of SnO_(2)film quality,interfacial energy band alignment,charge extraction efficiency,and defect state suppression.The photodetector optimized by UV327's tautomer achieves an ultralow dark current density of 3.22×10^(-10)A cm^(-2),an enhanced linear dynamic range of 94.14 d B,and a fast response time of 23.35/26.19μs.Notably,unencapsulated devices maintain a stable response at 3900 Hz following 300 h exposure to 40%±5%relative humidity and 30 h UV irradiation.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.52272168 and 62322410)the Anhui Provincial Natural Science Foundation(Grant No.2308085J08)USTC Bihe Youth Program for Interdisciplinary Innovation(Grant No.BH-202514).
文摘Solar-blind ultraviolet photodetectors(UV PDs),capable of detecting UV radiation without interference from sun-light,have attracted significant interest.Herein,we propose a 0D/1D heterostructure for UV PDs,which was fabricated by spin-coating MoS_(2)quantum dots onto p-AlGaN nanowires.The device achieves a high responsivity of 175.5 mA/W and a fast response speed of 83 ms at 250 nm illumination under self-powered mode,which improved nearly 1235%and 521%after MoS_(2)decoration,respectively.These improvements can be attributed to the type-Ⅱheterostructure formed between p-AlGaN and MoS_(2),which facilitates enhanced charge separation and carrier transport.Later,we demonstrate the implementation of this device in optical communication,achieving high-accuracy transmission of"GaN"ASCII code signals.Such a 0D/1D het-erostructure provides an effective strategy for high-performance solar-blind UV PD.
基金supported by the National Key R&D Program of China(Grant No.2024YFA1211300)Outstanding Youth Foundation of NSFC(Grant No.62322515)+5 种基金Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)Shanghai Natural Science Foundation Project(Grant No.24ZR1493100)International Partnership Program of Chinese Academy of Sciences(Grant No.112GJHZ2024039FN)the support from Analytical Instrumentation Center(#SPST-AIC10112914)Soft Matter Nanofab(#SPST-SMN180827)Quantum Device Lab,Shanghai Tech University。
文摘Infrared and terahertz waves constitute pivotal bands within the electromagnetic spectrum,distinguished by their robust penetration capabilities and non-ionizing nature.These wavebands offer the potential for achieving high-resolution and non-destructive detection methodologies,thereby possessing considerable research significance across diverse domains including communication technologies,biomedical applications,and security screening systems.Two-dimensional materials,owing to their distinctive optoelectronic attributes,have found widespread application in photodetection endeavors.Nonetheless,their efficacy diminishes when tasked with detecting lower photon energies.Furthermore,as the landscape of device integration evolves,two-dimensional materials struggle to align with the stringent demands for device superior performance.Topological materials,with their topologically protected electronic states and non-trivial topological invariants,exhibit quantum anomalous Hall effects and ultra-high carrier mobility,providing a new approach for seeking photosensitive materials for infrared and terahertz photodetectors.This article introduces various types of topological materials and their properties,followed by an explanation of the detection mechanism and performance parameters of photodetectors.Finally,it summarizes the current research status of near-infrared to far-infrared photodetectors and terahertz photodetectors based on topological materials,discussing the challenges faced and future prospects in their development.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.RS-2022–00165798)Anhui Natural Science Foundation(No.2308085MF211)The authors extend their appreciation to the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under Grant Number(R.G.P.2/491/45).
文摘The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(PDs)due to their unique optoelectronic properties and flexible synthesis routes.This review explores the approaches used in the development and use of optoelectronic devices made of different nanoscale perovskite architectures,including quantum dots,nanosheets,nanorods,nanowires,and nanocrystals.Through a thorough analysis of recent literature,the review also addresses common issues like the mechanisms underlying the degradation of perovskite PDs and offers perspectives on potential solutions to improve stability and scalability that impede widespread implementation.In addition,it highlights that photodetection encompasses the detection of light fields in dimensions other than light intensity and suggests potential avenues for future research to overcome these obstacles and fully realize the potential of nanoscale perovskite materials in state-of-the-art photodetection systems.This review provides a comprehensive overview of nanoscale perovskite PDs and guides future research efforts towards improved performance and wider applicability,making it a valuable resource for researchers.
基金supported by the National Natural Science Foundation of China (No. 62204079)the Science and Technology Development Project of Henan Province (Nos.202300410048, 202300410057)+2 种基金the China Postdoctoral Science Foundation (No. 2022M711037)the Intelligence Introduction Plan of Henan Province in 2021 (No. CXJD2021008)Henan University Fund。
文摘Quantum dot(QD)-based infrared photodetector is a promising technology that can implement current monitoring,imaging and optical communication in the infrared region. However, the photodetection performance of self-powered QD devices is still limited by their unfavorable charge carrier dynamics due to their intrinsically discrete charge carrier transport process. Herein, we strategically constructed semiconducting matrix in QD film to achieve efficient charge transfer and extraction.The p-type semiconducting CuSCN was selected as energy-aligned matrix to match the n-type colloidal PbS QDs that was used as proof-of-concept. Note that the PbS QD/CuSCN matrix not only enables efficient charge carrier separation and transfer at nano-interfaces but also provides continuous charge carrier transport pathways that are different from the hoping process in neat QD film, resulting in improved charge mobility and derived collection efficiency. As a result, the target structure delivers high specific detectivity of 4.38 × 10^(12)Jones and responsivity of 782 mA/W at 808 nm, which is superior than that of the PbS QD-only photodetector(4.66 × 10^(11)Jones and 338 mA/W). This work provides a new structure candidate for efficient colloidal QD based optoelectronic devices.
基金supported by a Commercialization Promotion Agency for R&D Outcomes(COMPA)Grant funded by the Korean Government(Ministry of Science and ICT)(No.RS-2023-00304743)the National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIT)(No.2022M3J7A1066428)"Regional Innovation Strategy(RIS)"through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(MOE)(No.2023RIS-008).
文摘A polarization-sensitive and flexible photodetector was fabricated through the precise alignment of perovskite nanowires(NWs)using a brush coating technique.The alignment of the NWs was meticulously examined,considering various chemical properties of the solvent,such as boiling point,viscosity,and surface tension.Notably,when the NWs were brush-coated with toluene dispersion,the NWs were aligned in higher order than those processed from octane dispersion.The degree of alignment was correlated with the photodetector property.Especially,the well-aligned NW photodetector exhibited a two-fold disparity in current response contingent on the polarization direction.Furthermore,even after enduring 500 bending cycles,the device retained 80%of its photodetector performance.This approach underscores the potential of solution-processed flexible photodetectors for advanced optical applications under dynamic operating conditions.
基金supported by the National Natural Science Foundation of China(52303257,52321006,T2394480,and T2394484)the National Key R&D Program of China(Grant No.2023YFE0111500)+3 种基金Key Research&Development and Promotion of Special Project(Scientific Problem Tackling)of Henan Province(242102211090)the China Postdoctoral Science Foundation(2023TQ0300,and 2023M743171)the Postdoctoral Fellowship Program(Grade B)of China Postdoctoral Science Foundation(GZB20230666)College Student Innovation and Entrepreneurship Training Program of Zhengzhou University(202410459200)。
文摘Flexible wearable optoelectronic devices fabricated fromorganic–inorganic hybrid perovskites significantly accelerate the developmentof portable energy,biomedicine,and sensing fields,but their poor thermal stabilityhinders further applications.Conversely,all-inorganic perovskites possessexcellent thermal stability,but black-phase all-inorganic perovskite filmusually requires high-temperature annealing steps,which increases energy consumptionand is not conducive to the fabrication of flexible wearable devices.In this work,an unprecedented low-temperature fabrication of stable blackphaseCsPbI3perovskite films is demonstrated by the in situ hydrolysis reactionof diphenylphosphinic chloride additive.The released diphenyl phosphateand chloride ions during the hydrolysis reaction significantly lower the phasetransition temperature and effectively passivate the defects in the perovskitefilms,yielding high-performance photodetectors with a responsivity of 42.1 AW−1 and a detectivity of 1.3×10^(14)Jones.Furthermore,high-fidelity imageand photoplethysmography sensors are demonstrated based on the fabricated flexible wearable photodetectors.This work provides a newperspective for the low-temperature fabrication of large-area all-inorganic perovskite flexible optoelectronic devices.
基金Supported by National Key Research and Development Program of China(2022YFA1404201)National Natural Science Foundation of China(62205187,U23A20380,U22A2091,62222509,62127817,62075120)+3 种基金Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(IRT_17R70)Fundamental Research Program of Shanxi Province(202103021223032,202303021222031)Project Funded by China Postdoctoral Science Foundation(2022M722006)Fund for Shanxi“1331 Project”Key Subjects Construction。
文摘Tin-lead(Sn-Pb)mixed perovskites are extensively investigated in near-infrared(NIR)photodetectors(PDs)owing to their excellent photoelectric performance.However,achieving high-performance Sn-Pb mixed PDs remains challenging,primarily because of the rapid crystallization and the susceptibility of Sn^(2+) to oxidation.To ad⁃dress these issues,this study introduces the multifunctional molecules 2,3-difluorobenzenamine(DBM)to modulate the crystallization of Sn-Pb mixed perovskites and retard the oxidation of Sn^(2+),thereby significantly enhancing film quality.Compared with the pristine film,Sn-Pb mixed perovskite films modulated by DBM molecules exhibit a high⁃ly homogeneous morphology,reduced roughness and defect density.The self-powered NIR PDs fabricated with the improved films have a spectral response range from 300 nm to 1100 nm,a peak responsivity of 0.51 A·W^(-1),a spe⁃cific detectivity as high as 2.46×10^(11)Jones within the NIR region(780 nm to 1100 nm),a linear dynamic range ex⁃ceeding 152 dB,and ultrafast rise/fall time of 123/464 ns.Thanks to the outstanding performance of PDs,the fabri⁃cated 5×5 PDs array demonstrates superior imaging ability in the NIR region up to 980 nm.This work advances the development of Sn-Pb mixed perovskites for NIR detection and paves the way for their commercialization.
基金supported by the Director’s Fund for the‘Climbing Plan’of the National Space Science Centre of the Chinese Academy of Sciences(No.E2PD10011S)the National Engineering Research Centre for Mobile Private Networks Project(No.BJTU20221102).
文摘This study begins with the fabrication and simulation of high-performance back-illuminated AlGaN-based solar-blind ultraviolet(UV)photodetectors.Based on the photodetectors,a low-noise,high-gain UV detection system circuit is designed and fabricated,enabling the detection,acquisition,and calibration of weak solar-blind UV signals.Experimental results demonstrate that under zero bias conditions,with a UV light power density of 3.45μW/cm^(2) at 260 nm,the sample achieves a peak responsivity(R)of 0.085 A·W^(−1),an external quantum efficiency(EQE)of 40.7%,and a detectivity(D^(*))of 7.46×10^(12) cm·Hz^(1/2)·W^(−1).The system exhibits a bandpass characteristic within the 240–280 nm wavelength range,coupled with a high signal-to-noise ratio(SNR)of 39.74 dB.
基金supported by the National Natural Science Foundation of China(Nos.52272175,U2001215 and 12474226)the Guangzhou Science and Technology Programme(No.2025A04J2596)+2 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515012688,2022A1515011487,2021A1515110403 and 2023A1515010652)the Young Top Talents Program(No.2021QN02C068)State Key Laboratory of Optoelectronic Materials and Technologies of Sun Yat-sen University.
文摘Pulsed-laser deposition has been developed to prepare large-area In_(2)S_(3)nanofilms and their photoelectric characteristics have been investigated.The In_(2)S_(3)nanofilm grown under 500℃is highly oriented along the(103)direction with exceptional crystallinity.The corresponding(103)-oriented In_(2)S_(3)photodetectors exhibit broadband photoresponse from 370.6 nm to 1064 nm.Under 635 nm illumination,the optimized responsivity,external quantum efficiency,and detectivity reach 19.8 A/W,3869%,and 2.59×10^(12)Jones,respectively.In addition,the device exhibits short rise/decay time of 3.9/3.0 ms.Of note,first-principles calculations have unveiled that the effective carrier mass along the(103)lattice plane is much smaller than those along the(100),(110)and(111)lattice planes,which thereby enables high-efficiency transport of photocarriers and thereby the excellent photosensitivity.Profited from the sizable bandgap,the In_(2)S_(3)photodetectors also showcase strong robustness against elevated operating temperature.In the end,proof-of-concept imaging application beyond human vision and under high operating temperature as well as heart rate monitoring have been achieved by using the In_(2)S_(3)device of the sensing component.This study introduces a novel crystal orientation engineering paradigm for the implementation of next-generation advanced optoelectronic systems.
基金Liming Gao acknowledges funding from the National Natural Science Foundation of China(No.61727805).
文摘The rise of smart wearable devices has driven the demand for flexible,high-performance optoelectronic devices with low power and easy high-density integration.Emerging Two-dimensional(2D)materials offer promising solutions.However,the use of 3D metal in traditional 2D devices often leads to Fermi-level pinning,compromising device performance.2D metallic materials,such as graphene and 2H-phase NbSe_(2),present a new avenue for addressing this issue and constructing high-performance,low-power photodetectors.In this work,we designed an all-2D asymmetric contacts photodetector using Gr and NbSe_(2)as electrodes for the 2D semiconductor WSe_(2).The asymmetric Schottky barriers and built-in electric fields facilitated by this architecture resulted in outstanding photovoltaic characteristics and self-powered photodetection.Under zero bias,the device exhibited a responsivity of 287 mA/W,a specific detectivity of 5.3×10^(11)Jones,and an external quantum efficiency of 88%.It also demonstrated an ultra-high light on/offratio(1.8×10^(5)),ultra-fast photoresponse speeds(80/72μs),broad-spectrum responsiveness(405980 nm),and exceptional cycling stability.The applications of the Gr/WSe_(2)/NbSe_(2)heterojunction in imaging and infrared optical communication have been explored,underscoring its significant potential.This work offers an idea to construct all-2D ultrathin optoelectronic devices.
文摘It is regretful that the data error due to the large number of samples tested.The correct data and figure should be as follows:This correction have no impact on the remainder of the manuscript,the interpretation of the data,or the conclusions reached.The authors would like to apologize for any inconvenience caused.
基金financially supported by National Natural Science Foundation of China(Nos.U2001215,52272175,12104517)Natural Science Foundation of Guangdong Province(Nos.2022A1515011487,2021A1515110403)+1 种基金Young Top Talents Program(No.2021QN02C068)State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-sen University).
文摘Wearable photodetectors have come under the limelight of optoelectronic technologies on account of multiple advantages spanning light weight,easy-portability,excellent bendability,outstanding conformability,etc.Among diverse candidate materials,low-dimensional van der Waals materials(LDvdWMs)have emerged to be preeminent owing to the dangling-bond-free surface,exceptional carrier mobility,nanoscale dimensionality,and excellent light-harvesting capability.However,to date,the majority of flexible LDvdWM photodetectors have been fabricated through exfoliation-,transfer-,or solution-processing methods,which are plagued by limitations such as low production yield,inadequate photosensitivity,and sluggish response rate.Thus far,constructing LDvdWM photodetectors in situ on flexible substrates remains quite challenging due to the irreconcilable contradiction between the weak robustness of flexible polymer substrates against high temperature and the large thermal budget required for crystallization.This study develops scalable preparation of Sb_(2)Se_(3)nanofilm directly on flexible polyimide substrates by exploiting pulsed-laser deposition(PLD),where highly energetic species can be generated to enable overcoming the reaction barrier for crystallization at a relatively low temperature.The corresponding Sb_(2)Se_(3)photodetectors have exhibited high responsivity of 1.15 A/W,exceptional external quantum efficiency of 269%,and impressive specific detectivity reaching 2.4×10^(11)Jones,coupled with swift switching characteristics.Importantly,excellent durability to repeated bending treatments has been confirmed by the consistent photoresponse over 500 convex/concave bending cycles.Furthermore,the device has showcased strong robustness against extrinsic impinging.In the end,by using Sb_(2)Se_(3)photodetectors as sensing components,wide-band imaging beyond human vision and heart rate monitoring have been realized.This study has underscored the high efficacy of PLD for reconciling the long-standing contradiction between the weak robustness of flexible polymer substrates against high temperature and the substantial thermal energy required for crystallization,opening new opportunities towards next-generation wearable optoelectronic industry.
基金Funded by the Research Project of Shenzhen Science and Technology Innovation Committee(No.JCYJ20180306170801080)。
文摘Planar-structured amorphous InGaZnO(a-IGZO)film-based UV photodetectors with different ITO interdigitated electrode spacings were developed on flexible PI substrates via radio frequency magnetron sputtering and non-lithographic fabrication processes.The effects of oxygen flow rate on the surface morphology,electrical transport,and chemical bonding properties of the a-IGZO films were systematically investigated to optimize the performance of the flexible detector.The average transmittance of the flexible a-IGZO photodetector is over 90%in the visible spectral range with a large photo-to-dark current ratio of 3.9×10^(3)under 360 nm UV illumination.The photocurrent of the detectors increases with decreasing the electrode spacing,which is attribute to formation of higher electrical field and drifting more electron-hole pairs to the electrode with shortening the electrode spacing.Under a UV illumination intensity of 9.1 mW/cm~2,the highest responsivity and detectivity of the photodetector with the electrode spacing of 0.4 mm reach 62.1 mA/W and2.83×10^(11)cm·Hz^(1/2)·W^(-1)at 11 V bias voltage,respectively.The flexible detector exhibits enhanced photoresponse performance with the rise and decay time of 2.02 and 0.94 s,respectively.These results can be used in a practical scheme to design and realize the a-IGZO based UV photodetectors with excellent transparency and flexibility for wearable UV monitoring applications.
基金support from the National Natural Science Foundation of China under Grant(No.62174093)the Ningbo Youth Science and Technology Innovation Leading Talent Project under Grant(No.2023QL006)support from the Shanghai Rising-Star Program(No.21QA1410900)。
文摘Graphene has garnered significant attention in photodetection due to its exceptional optical,electrical,mechanical,and thermal properties.However,the practical application of two-dimensional(2D)graphene in optoelectronic fields is limited by its weak light absorption(only 2.3%)and zero bandgap characteristics.Increasing light absorption is a critical scientific challenge for developing high-performance graphene-based photodetectors.Three-dimensional(3D)graphene comprises vertically grown stacked 2D-graphene layers and features a distinctive porous structure.Unlike 2D-graphene,3D-graphene offers a larger specific surface area,improved electrochemical activity,and high chemical stability,making it a promising material for optoelectronic detection.Importantly,3D-graphene has an optical microcavity structure that enhances light absorption through interaction with incoming light.This paper systematically reviews and analyzes the current research status and challenges of 3D-graphene-based photodetectors,aiming to explore feasible development paths for these devices and promote their industrial application.
基金supported by Open Research Fund of Songshan Lake Materials Laboratory(No.2023SLABFK08)Key Research and Development Program of Hunan Province(No.2022GK2007)+2 种基金Key Project from Department Education of Hunan Province(No.22A0123)National Natural Science Foundation of China(No.11974301)Graduate Student Research Innovation of Xi-angtan University(No.XDCX2024Y198).
文摘Two-dimensional(2D)noble transition-metal dichalcogenide materials(NTMDs)have garnered remarkable attention due to their intriguing properties exhibiting potential applications in nanoelectronics,optoelectronics,and photonics.The electronic structure and physical properties of 2D NTMDs can be effectively modulated using alloy engineering strategy.Nevertheless,the precise growth of wafer-scale 2D NTMDs alloys remains a significant challenge.In this work,we have achieved the controllable preparation of wafer-scale(2-inch)2D PdS_(2x)Se_(2(1-x)) nanofilms(NFs)with fully tunable compositions on various substrates using pre-deposited Pd NFs assisted chemical vapor deposition technique.High-performance photodetectors based on the PdS_(2x)Se_(2(1-x))NFs were fabricated,which exhibit broadband photodetection performance from visible to near-infrared(NIR)wavelength range at room temperature.Significantly,the PdS0.9Se1.1-based photodetectors display a responsivity up to 0.192 A W^(-1) and a large specific detectivity of 5.5×1011 Jones for 850 nm light,enabling an excellent high-resolution NIR single-pixel imaging(SPI)without an additional filtering circuit.Our work paves a new route for the controlled synthesis of wafer-scale and high-quality 2D NTMDs alloy NFs,which is essential for designing advanced optoelectronic devices.
文摘Correction to:Opto-Electronic Science https://www.oejournal.org/oes/article/doi/10.29026/oes.2024.230029 published online 21 March 2024.After the publication of this article1,it was brought to our attention that the inset image and absorption spectrum in Fig.1(b)contained a mistake,probably leading to misunderstandings.The inset image and the absorption spectrum in Fig.1(b)were not based on the specific batch of PbS colloidal quantum dots(CQDs)used in this work.
基金financially supported by the National Natural Science Foundation of China (Grant No. 61991442)。
文摘Quantum well infrared photodetectors(QWIPs) based on intersubband transitions hold significant potential for high bandwidth operation. In this work, we establish a carrier transport optimization model incorporating electron injection at the emitter to investigate the carrier dynamics time and impedance spectroscopy in GaAs/AlGaAs QWIPs. Our findings provide novel evidence that the escape time of electrons is the key limiting factor for the 3-dB bandwidth of QWIPs. Moreover, to characterize the impact of carrier dynamics time and non-equilibrium space charge region on impedance, we developed an equivalent circuit model where depletion region resistance and capacitance are employed to describe non-equilibrium space charge region. Using this model, we discovered that under illumination, both net charge accumulation caused by variations in carrier dynamics times within quantum wells and changes in width of non-equilibrium space charge region exert different dominant influences on depletion region capacitance at various doping concentrations.
