Miniaturized light sources at telecommunication wavelengths are essential components for on-chip optical communication systems.Here,we report the growth and fabrication of highly uniform p-i-n core-shell InGaAs/InP si...Miniaturized light sources at telecommunication wavelengths are essential components for on-chip optical communication systems.Here,we report the growth and fabrication of highly uniform p-i-n core-shell InGaAs/InP single quantum well(QW)nanowire array light emitting diodes(LEDs)with multi-wavelength and high-speed operations.Two-dimensional cathodoluminescence mapping reveals that axial and radial QWs in the nanowire structure contribute to strong emission at the wavelength of~1.35 and~1.55μm,respectively,ideal for low-loss optical communications.As a result of simultaneous contributions from both axial and radial QWs,broadband electroluminescence emission with a linewidth of 286 nm is achieved with a peak power of~17μW.A large spectral blueshift is observed with the increase of applied bias,which is ascribed to the band-filling effect based on device simulation,and enables voltage tunable multi-wavelength operation at the telecommunication wavelength range.Multi-wavelength operation is also achieved by fabricating nanowire array LEDs with different pitch sizes on the same substrate,leading to QW formation with different emission wavelengths.Furthermore,high-speed GHz-level modulation and small pixel size LED are demonstrated,showing the promise for ultrafast operation and ultracompact integration.The voltage and pitch size controlled multi-wavelength highspeed nanowire array LED presents a compact and efficient scheme for developing high-performance nanoscale light sources for future optical communication applications.展开更多
Air quality is deteriorating due to continuing urbanization and industrialization.In particular,nitrogen dioxide(NO_(2))is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous...Air quality is deteriorating due to continuing urbanization and industrialization.In particular,nitrogen dioxide(NO_(2))is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous in urban life.To address this issue,we report a high-performance flexible indium phosphide nanomembrane NO_(2)sensor for real-time air quality monitoring.An ultralow limit of detection of~200 ppt and a fast response have been achieved with this device by optimizing the film thickness and doping concentration during indium phosphide epitaxy.By varying the film thickness,a dynamic range of values for NO_(2)detection from parts per trillion(ppt)to parts per million(ppm)level have also been demonstrated under low bias voltage and at room temperature without additional light activation.Flexibility measurements show an adequately stable response after repeated bending.On-site testing of the sensor in a residential kitchen shows that NO_(2)concentration from the gas stove emission could exceed the NO_(2)Time Weighted Average limit,i.e.,200 ppb,highlighting the significance of real-time monitoring.Critically,the indium phosphide nanomembrane sensor element cost is estimated at<0.1 US$due to the miniatured size,nanoscale thickness,and ease of fabrication.With these superior performance characteristics,low cost,and real-world applicability,our indium phosphide nanomembrane sensors offer a promising solution for a variety of air quality monitoring applications.展开更多
Background:Statins,a first-line therapeutic option for atherosclerotic cardiovascular disease(ASCVD),have prompted concerns regarding dysglycemia and diabetes,thus posing a dilemma in treating patients with prediabete...Background:Statins,a first-line therapeutic option for atherosclerotic cardiovascular disease(ASCVD),have prompted concerns regarding dysglycemia and diabetes,thus posing a dilemma in treating patients with prediabetes.Xuezhikang(XZK)decreases blood cholesterol levels without affecting glucose metabolism,and may serve as a potential substitute.Methods:The XTREME study is a prospective,randomized,open-label,multi-center trial evaluating whether XZK 1200 mg/d,compared with atorvastatin 20 mg/d,has favorable effects on HbA1c levels after 24 weeks of treatment in patients with dyslipidemia and prediabetes.After a 1-week run-in period for adherence assessment,the study will ran-domly assign(1:1)392 patients meeting the protocol inclusion criteria to one of two treatment groups:an experimental group(XZK 1200 mg/day)or a control group(atorvastatin 20 mg/day).All participants will be recruited from approxi-mately 20 Chinese medical centers.The last participant is planned to be recruited before December 2023.The primary endpoint will be change in HbA1c level from baseline to 24 weeks,or before anti-diabetic therapy initiation within 24 weeks.The key secondary outcomes will include other biomarkers reflecting blood glucose or lipid metabolism.Discussion:Delaying diabetes is desirable for individuals with prediabetes.The XTREME trial presents a unique oppor-tunity to demonstrate whether XZK might provide an alternative to statins for patients with dyslipidemia and prediabetes.展开更多
The two-dimensional(2D)materials have been widely developed recently in material characteristics with advanced optical and electrical properties,and they have been extensively studied as candidates for the next genera...The two-dimensional(2D)materials have been widely developed recently in material characteristics with advanced optical and electrical properties,and they have been extensively studied as candidates for the next generation of optoelectronic devices.This review will mainly focus on the preparation methods and the light emitting applications of 2D transition metal dichalcogenides(TMDs),2D black phosphorene(BP)and 2D perovskites.The review will first introduce the preparation methods for TMDs and BP.Due to the variations of band structure,exciton binding energies and light-matter interaction in TMDs and BP,the different light emitting devices(LEDs)designs based on TMDs and BP will be discussed and summarized.Then the review will turn the focus to 2D perovskites,starting with a description of the preparation methods for the different structural perovskites.In order to review and summarize the achievements of 2D perovskites-based LEDs,the high efficiency perovskites LEDs are discussed.Finally,the review will present challenges,opportunities,and outlook for the future development of 2D materials-based light emitting applications.展开更多
The demand for future semiconductor devices with enhanced performance and lower cost has driven the development of epitaxial growth of high quality,free-standing semiconductor thin film materials without the requireme...The demand for future semiconductor devices with enhanced performance and lower cost has driven the development of epitaxial growth of high quality,free-standing semiconductor thin film materials without the requirement of lattice matching to the substrate,as well as their transfer to other substrates and associated device processing technology.This work presents a study on the van der Waals epitaxy based molecular beam epitaxy of CdSe thin films on two-dimensional layered mica substrates,as well as related etch-free layer transfer technology of large area,free-standing layers and their application in flexible photodetectors for full-color imaging.The photoconductor detectors based on these flexible CdSe thin films demonstrate excellent device performance at room temperature in terms of responsivity(0.2 A·W^(-1))and detectivity(1.5×10^(12)Jones),leading to excellent full-color imaging quality in the visible spectral range.An etch-free and damage-free layer transfer method has been developed for transferring these CdSe thin films from mica to other substrate for further device processing and integration.These results demonstrate the feasibility of van der Waals epitaxy method for growing high quality,large area,and free-standing epitaxial layers without the requirement for lattice matching to substrate for applications in low-cost flexible and/or monolithic integrated optoelectronic devices.展开更多
Vehicle Re-identification(Re-ID)has drawn extensive exploration recently;nevertheless,the issue of accurately distinguishing features in latent space across varying vehicle poses,remains a challenging hurdle for real-...Vehicle Re-identification(Re-ID)has drawn extensive exploration recently;nevertheless,the issue of accurately distinguishing features in latent space across varying vehicle poses,remains a challenging hurdle for real-world application of Vehicle Re-ID.To address this challenge,we supply a novel idea which projects the various-pose vehicle images into a unified target pose so as to promote the discriminative capability of vehicle Re-ID model.Acknowledging the labor and cost of paired data for the same vehicle images across different traffic surveillance cameras in practical scenarios,we propose the pioneering Pair-flexible Pose Guided Image Synthesis for vehicle Re-ID,denominated as VehicleGAN.Our method is adept at both supervised(paired images of same vehicle)and unsupervised(unpaired images of any vehicle)settings,and bypasses the need of geometric 3D model information.Furthermore,we propose a novel Joint Metric Learning(JML)method to facilitate the effective fusion of both real and synthetic data.Comprehensive experimental analyses conducted on the public VeRi-776 and VehicleID datasets substantiate the precision and efficacy of our proposed VehicleGAN and JML.展开更多
Narrowband red,green,blue self-filtering perovskite photodetectors and a broadband white photodetector are incorporated into a single pixel imaging camera to mimic the long-,medium-,and short-wavelength cone cells and...Narrowband red,green,blue self-filtering perovskite photodetectors and a broadband white photodetector are incorporated into a single pixel imaging camera to mimic the long-,medium-,and short-wavelength cone cells and rod cells in human visual system,leading to the demonstration of high-resolution color images in diffuse mode.展开更多
Semiconductor nanowires(NWs)could simultaneously provide gain medium and optical cavity for performing nanoscale lasers with easy integration,ultracompact footprint,and low energy consumption.Here,we report Ⅲ-Ⅴsemic...Semiconductor nanowires(NWs)could simultaneously provide gain medium and optical cavity for performing nanoscale lasers with easy integration,ultracompact footprint,and low energy consumption.Here,we report Ⅲ-Ⅴsemiconductor NW lasers can also be used for self-frequency conversion to extend their output wavelengths,as a result of their non-centrosymmetric crystal structure and strongly localized optical field in the NWs.From a GaAs/In0.16Ga0.84As core/shell NW lasing at 1016 nm,an extra visible laser output at 508 nm is obtained via the process of second-harmonic generation,as confirmed by the far-field polarization dependence measurements and numerical modeling.From another NW laser with a larger diameter which supports multiple fundamental lasing wavelengths,multiple self-frequency-conversion lasing modes are observed due to second-harmonic generation and sum-frequency generation.The demonstrated self-frequency conversion of NW lasers opens an avenue for extending the working wavelengths of nanoscale lasers,even to the deep ultraviolet and THz range.展开更多
Ⅱ-Ⅴsemiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices.However,solely relying on their intrinsic physical and material properties sometimes limits device fun...Ⅱ-Ⅴsemiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices.However,solely relying on their intrinsic physical and material properties sometimes limits device functionalities to meet the increasing demands in versatile and complex electronic world.By leveraging the distinctive nature of the one-dimensional geometry and large surface-to-volume ratio of the nanowires,new properties can be attained through monolithic integration of conventional nanowires with other easy-synthesized functional materials.Herein,we combine high-crystal-quality lInitridle nanowires with amorphous molybdenum sulfides(a-MoS)to construct II.nitride/a-MoS_(x) core-shell nanostructures.Upon light ilumination,such nanostructures exhibit striking spectrally distinctive photodetection characteristic in photoelectrochemical environment,demonstrating a negative photoresponsivity of-100.42 mA W^(-1)under 254 nm ilumination,and a positive photoresponsivity of 29.5 mA W^(-1)under 365 nm ilumination.Density functional theory calculations reveal that the successful surface modifcation of the nanowires via a-MoS_(x)decoration accelerates the reaction process at the electrolyte/nanowire interface,leading to the generation of opposite photocurrent signals under different photon ilumination.Most importantly,such polarity-switchable photoconductivity can be further tuned for multiple wavelength bands photodetection by simply adjusting the surrounding environment and/or tailoring the nanowire composition,showing great promise to build light-wavelength controllable sensing devices in the future.展开更多
Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the tele...Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the telecom band.Here,we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy.To reduce optical loss and tailor the cavity mode,a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality.Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO_(2) mask interface,stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of~28.2μJ cm^(−2) per pulse and a high characteristic temperature of~128 K.By fine-tuning the In composition of the quantum wells,room temperature,single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range,spanning from 940 nm to the telecommunication O and C bands.Our research indicates that through a carefully designed facet engineering strategy,highly ordered,uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate,paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems.展开更多
文摘Miniaturized light sources at telecommunication wavelengths are essential components for on-chip optical communication systems.Here,we report the growth and fabrication of highly uniform p-i-n core-shell InGaAs/InP single quantum well(QW)nanowire array light emitting diodes(LEDs)with multi-wavelength and high-speed operations.Two-dimensional cathodoluminescence mapping reveals that axial and radial QWs in the nanowire structure contribute to strong emission at the wavelength of~1.35 and~1.55μm,respectively,ideal for low-loss optical communications.As a result of simultaneous contributions from both axial and radial QWs,broadband electroluminescence emission with a linewidth of 286 nm is achieved with a peak power of~17μW.A large spectral blueshift is observed with the increase of applied bias,which is ascribed to the band-filling effect based on device simulation,and enables voltage tunable multi-wavelength operation at the telecommunication wavelength range.Multi-wavelength operation is also achieved by fabricating nanowire array LEDs with different pitch sizes on the same substrate,leading to QW formation with different emission wavelengths.Furthermore,high-speed GHz-level modulation and small pixel size LED are demonstrated,showing the promise for ultrafast operation and ultracompact integration.The voltage and pitch size controlled multi-wavelength highspeed nanowire array LED presents a compact and efficient scheme for developing high-performance nanoscale light sources for future optical communication applications.
基金A.T.gratefully acknowledges the support of the Australian Research Council for a Future Fellowship(FT200100939)Discovery grant DP190101864+1 种基金A.T.also acknowledges financial support from the North Atlantic Treaty Organization Science for Peace and Security Programme project AMOXES(#G5634)ARC-NISDRG-NS210100083.
文摘Air quality is deteriorating due to continuing urbanization and industrialization.In particular,nitrogen dioxide(NO_(2))is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous in urban life.To address this issue,we report a high-performance flexible indium phosphide nanomembrane NO_(2)sensor for real-time air quality monitoring.An ultralow limit of detection of~200 ppt and a fast response have been achieved with this device by optimizing the film thickness and doping concentration during indium phosphide epitaxy.By varying the film thickness,a dynamic range of values for NO_(2)detection from parts per trillion(ppt)to parts per million(ppm)level have also been demonstrated under low bias voltage and at room temperature without additional light activation.Flexibility measurements show an adequately stable response after repeated bending.On-site testing of the sensor in a residential kitchen shows that NO_(2)concentration from the gas stove emission could exceed the NO_(2)Time Weighted Average limit,i.e.,200 ppb,highlighting the significance of real-time monitoring.Critically,the indium phosphide nanomembrane sensor element cost is estimated at<0.1 US$due to the miniatured size,nanoscale thickness,and ease of fabrication.With these superior performance characteristics,low cost,and real-world applicability,our indium phosphide nanomembrane sensors offer a promising solution for a variety of air quality monitoring applications.
文摘Background:Statins,a first-line therapeutic option for atherosclerotic cardiovascular disease(ASCVD),have prompted concerns regarding dysglycemia and diabetes,thus posing a dilemma in treating patients with prediabetes.Xuezhikang(XZK)decreases blood cholesterol levels without affecting glucose metabolism,and may serve as a potential substitute.Methods:The XTREME study is a prospective,randomized,open-label,multi-center trial evaluating whether XZK 1200 mg/d,compared with atorvastatin 20 mg/d,has favorable effects on HbA1c levels after 24 weeks of treatment in patients with dyslipidemia and prediabetes.After a 1-week run-in period for adherence assessment,the study will ran-domly assign(1:1)392 patients meeting the protocol inclusion criteria to one of two treatment groups:an experimental group(XZK 1200 mg/day)or a control group(atorvastatin 20 mg/day).All participants will be recruited from approxi-mately 20 Chinese medical centers.The last participant is planned to be recruited before December 2023.The primary endpoint will be change in HbA1c level from baseline to 24 weeks,or before anti-diabetic therapy initiation within 24 weeks.The key secondary outcomes will include other biomarkers reflecting blood glucose or lipid metabolism.Discussion:Delaying diabetes is desirable for individuals with prediabetes.The XTREME trial presents a unique oppor-tunity to demonstrate whether XZK might provide an alternative to statins for patients with dyslipidemia and prediabetes.
文摘The two-dimensional(2D)materials have been widely developed recently in material characteristics with advanced optical and electrical properties,and they have been extensively studied as candidates for the next generation of optoelectronic devices.This review will mainly focus on the preparation methods and the light emitting applications of 2D transition metal dichalcogenides(TMDs),2D black phosphorene(BP)and 2D perovskites.The review will first introduce the preparation methods for TMDs and BP.Due to the variations of band structure,exciton binding energies and light-matter interaction in TMDs and BP,the different light emitting devices(LEDs)designs based on TMDs and BP will be discussed and summarized.Then the review will turn the focus to 2D perovskites,starting with a description of the preparation methods for the different structural perovskites.In order to review and summarize the achievements of 2D perovskites-based LEDs,the high efficiency perovskites LEDs are discussed.Finally,the review will present challenges,opportunities,and outlook for the future development of 2D materials-based light emitting applications.
基金supported by the Australian Research Council(Nos.FT130101708,DP200103188,DP170104562,LP170100088,and LEI70100233)。
文摘The demand for future semiconductor devices with enhanced performance and lower cost has driven the development of epitaxial growth of high quality,free-standing semiconductor thin film materials without the requirement of lattice matching to the substrate,as well as their transfer to other substrates and associated device processing technology.This work presents a study on the van der Waals epitaxy based molecular beam epitaxy of CdSe thin films on two-dimensional layered mica substrates,as well as related etch-free layer transfer technology of large area,free-standing layers and their application in flexible photodetectors for full-color imaging.The photoconductor detectors based on these flexible CdSe thin films demonstrate excellent device performance at room temperature in terms of responsivity(0.2 A·W^(-1))and detectivity(1.5×10^(12)Jones),leading to excellent full-color imaging quality in the visible spectral range.An etch-free and damage-free layer transfer method has been developed for transferring these CdSe thin films from mica to other substrate for further device processing and integration.These results demonstrate the feasibility of van der Waals epitaxy method for growing high quality,large area,and free-standing epitaxial layers without the requirement for lattice matching to substrate for applications in low-cost flexible and/or monolithic integrated optoelectronic devices.
文摘Vehicle Re-identification(Re-ID)has drawn extensive exploration recently;nevertheless,the issue of accurately distinguishing features in latent space across varying vehicle poses,remains a challenging hurdle for real-world application of Vehicle Re-ID.To address this challenge,we supply a novel idea which projects the various-pose vehicle images into a unified target pose so as to promote the discriminative capability of vehicle Re-ID model.Acknowledging the labor and cost of paired data for the same vehicle images across different traffic surveillance cameras in practical scenarios,we propose the pioneering Pair-flexible Pose Guided Image Synthesis for vehicle Re-ID,denominated as VehicleGAN.Our method is adept at both supervised(paired images of same vehicle)and unsupervised(unpaired images of any vehicle)settings,and bypasses the need of geometric 3D model information.Furthermore,we propose a novel Joint Metric Learning(JML)method to facilitate the effective fusion of both real and synthetic data.Comprehensive experimental analyses conducted on the public VeRi-776 and VehicleID datasets substantiate the precision and efficacy of our proposed VehicleGAN and JML.
文摘Narrowband red,green,blue self-filtering perovskite photodetectors and a broadband white photodetector are incorporated into a single pixel imaging camera to mimic the long-,medium-,and short-wavelength cone cells and rod cells in human visual system,leading to the demonstration of high-resolution color images in diffuse mode.
基金This work is supported by the National Key R&D Program of China(Grant Nos.2018YFA0307200 and 2017YFA0303800)the National Natural Science Foundation of China(Grant Nos.61775183,11634010,61905196,and 62005222)+1 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.3102017jc01001,3102019JC008,and 3102019110x032)the Natural Science Basic Research Program of Shaanxi Province(2020JQ 222).
文摘Semiconductor nanowires(NWs)could simultaneously provide gain medium and optical cavity for performing nanoscale lasers with easy integration,ultracompact footprint,and low energy consumption.Here,we report Ⅲ-Ⅴsemiconductor NW lasers can also be used for self-frequency conversion to extend their output wavelengths,as a result of their non-centrosymmetric crystal structure and strongly localized optical field in the NWs.From a GaAs/In0.16Ga0.84As core/shell NW lasing at 1016 nm,an extra visible laser output at 508 nm is obtained via the process of second-harmonic generation,as confirmed by the far-field polarization dependence measurements and numerical modeling.From another NW laser with a larger diameter which supports multiple fundamental lasing wavelengths,multiple self-frequency-conversion lasing modes are observed due to second-harmonic generation and sum-frequency generation.The demonstrated self-frequency conversion of NW lasers opens an avenue for extending the working wavelengths of nanoscale lasers,even to the deep ultraviolet and THz range.
基金National Natural Science Foundation of China(Grant Nos.51727901,52161145404,61905236,51961145110)the Fundamental Research Funds for the Central Universities(Grant Nos.WK300000009,WK2100230020)。
文摘Ⅱ-Ⅴsemiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices.However,solely relying on their intrinsic physical and material properties sometimes limits device functionalities to meet the increasing demands in versatile and complex electronic world.By leveraging the distinctive nature of the one-dimensional geometry and large surface-to-volume ratio of the nanowires,new properties can be attained through monolithic integration of conventional nanowires with other easy-synthesized functional materials.Herein,we combine high-crystal-quality lInitridle nanowires with amorphous molybdenum sulfides(a-MoS)to construct II.nitride/a-MoS_(x) core-shell nanostructures.Upon light ilumination,such nanostructures exhibit striking spectrally distinctive photodetection characteristic in photoelectrochemical environment,demonstrating a negative photoresponsivity of-100.42 mA W^(-1)under 254 nm ilumination,and a positive photoresponsivity of 29.5 mA W^(-1)under 365 nm ilumination.Density functional theory calculations reveal that the successful surface modifcation of the nanowires via a-MoS_(x)decoration accelerates the reaction process at the electrolyte/nanowire interface,leading to the generation of opposite photocurrent signals under different photon ilumination.Most importantly,such polarity-switchable photoconductivity can be further tuned for multiple wavelength bands photodetection by simply adjusting the surrounding environment and/or tailoring the nanowire composition,showing great promise to build light-wavelength controllable sensing devices in the future.
基金supported by the Key Research and Development Program(2022YFA1404800)the National Natural Science Foundation of China(62375226,62375225,12374359,62105267)+1 种基金the Fundamental Research Funds for the Central Universities(23GH02023)the Analytical&Testing Center of Northwestern Polytechnical University and the Australian Research Council.The Australian National Fabrication Facility ACT Node is acknowledged for access to the epitaxial growth facilities.
文摘Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the telecom band.Here,we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy.To reduce optical loss and tailor the cavity mode,a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality.Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO_(2) mask interface,stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of~28.2μJ cm^(−2) per pulse and a high characteristic temperature of~128 K.By fine-tuning the In composition of the quantum wells,room temperature,single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range,spanning from 940 nm to the telecommunication O and C bands.Our research indicates that through a carefully designed facet engineering strategy,highly ordered,uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate,paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems.
