As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal...As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.展开更多
Neuromorphic computing,inspired by the human brain,uses memristor devices for complex tasks.Recent studies show that self-organizing random nanowires can implement neuromorphic information processing,enabling data ana...Neuromorphic computing,inspired by the human brain,uses memristor devices for complex tasks.Recent studies show that self-organizing random nanowires can implement neuromorphic information processing,enabling data analysis.This paper presents a model based on these nanowire networks,with an improved conductance variation profile.We suggest using these networks for temporal information processing via a reservoir computing scheme and propose an efficient data encoding method using voltage pulses.The nanowire network layer generates dynamic behaviors for pulse voltages,allowing time series prediction analysis.Our experiment uses a double stochastic nanowire network architecture for processing multiple input signals,outperforming traditional reservoir computing in terms of fewer nodes,enriched dynamics and improved prediction accuracy.Experimental results confirm the high accuracy of this architecture on multiple real-time series datasets,making neuromorphic nanowire networks promising for physical implementation of reservoir computing.展开更多
Zinc oxide(ZnO)shows great potential in electronics,but its large intrinsic thermal conductivity limits its thermoelectric applications.In this work,we explore the significant carrier transport capacity and diameter-d...Zinc oxide(ZnO)shows great potential in electronics,but its large intrinsic thermal conductivity limits its thermoelectric applications.In this work,we explore the significant carrier transport capacity and diameter-dependent thermoelectric characteristics of wurtzite-ZnO(0001)nanowires based on first-principles and molecular dynamics simulations.Under the synergistic effect of band degeneracy and weak phonon-electron scattering,P-type(ZnO)_(73) nanowires achieve an ultrahigh power factor above 1500μW·cm^(-1)·K^(-2)over a wide temperature range.The lattice thermal conductivity and carrier transport properties of ZnO nanowires exhibit a strong diameter size dependence.When the ZnO nanowire diameter exceeds 12.72A,the carrier transport properties increase significantly,while the thermal conductivity shows a slight increase with the diameter size,resulting in a ZT value of up to 6.4 at 700 K for P-type(ZnO)_(73).For the first time,the size effect is also illustrated by introducing two geometrical configurations of the ZnO nanowires.This work theoretically depicts the size optimization strategy for the thermoelectric conversion of ZnO nanowires.展开更多
Electrochemical nitrate reduction(ENR)is an economical and eco-friendly method for converting industrial wastewater into valuable ammonia under atmospheric conditions.The main challenge lies in designing and developin...Electrochemical nitrate reduction(ENR)is an economical and eco-friendly method for converting industrial wastewater into valuable ammonia under atmospheric conditions.The main challenge lies in designing and developing highly durable ENR electrocatalysts.This study introduces defect-rich mesoporous CuO_(x) nanowires electrocatalyst synthesized using a novel solution-flame(sol-flame)hybrid method to control mesoporosity and introduce surface defects,thereby enhancing the electrochemical nitrate-toammonia production performance.We found surface defects(oxygen vacancies and Cu^(+))and unique mesoporous nanowire structure composed of tightly interconnected nanoparticles.The sol-flamesynthesized CuO_(x) nanowires(sf-CuO NWs)achieved superior ammonia yield rate(0.51 mmol h^(-1)cm^(-2)),faradaic efficiency(97.3%),and selectivity(86.2%)in 1 M KOH electrolyte(2000 ppm nitrate).This performance surpasses that of non-porous and less-defective CuO NWs and is attributed to the increased surface area and rapid electron transport facilitated by the distinctive morphology and generated defects.Theoretical calculation further suggests oxygen vacancies enhance NO_(3)^(-)adsorption on the sf-CuO NWs’surface and mitigate the competing hydrogen evolution reaction.This study outlines a strategic design and simple synthesis approach for nanowire electrocatalysts that boost the efficiency of electrochemical nitrate-to-ammonia conversion.展开更多
Semiconductor nanowires coupled to a superconductor provide a powerful testbed for quantum device physics such as Majorana zero modes and gate-tunable hybrid qubits.The performance of these quantum devices heavily rel...Semiconductor nanowires coupled to a superconductor provide a powerful testbed for quantum device physics such as Majorana zero modes and gate-tunable hybrid qubits.The performance of these quantum devices heavily relies on the quality of the induced superconducting gap.A hard gap.展开更多
Second harmonic generation(SHG)in optical materials serves as important techniques for laser source generations in awkward spectral ranges,physical identities of materials in crystalline symmetry and interfacial confi...Second harmonic generation(SHG)in optical materials serves as important techniques for laser source generations in awkward spectral ranges,physical identities of materials in crystalline symmetry and interfacial configuration.Here,we present a comprehensive review on SHGs in nanowires(NWs),which have been recognized as an important element in constructing photonic and optoelectronic devices with compact footprint and high quantum yield.Relying on NW’s one-dimensional geometry,its SHG could be employed as a sophisticated spectroscopy to determine the crystal phase and orientation,as well as the internal strain.The enhancements of SHG efficiency in NWs are discussed then,which were realized by hybrid integrating them with two-dimensional materials,nanophotonic and plasmonic structures.Finally,the potential applications of NW SHGs are concluded,including the areas of optical correlators and constructions of on-chip nano-laser sources.展开更多
We estimate the thermal properties of unsmooth Si nanowires,considering key factors such as size(diameter),surface texture(roughness)and quantum size effects(phonon states)at different temperatures.For nanowires with ...We estimate the thermal properties of unsmooth Si nanowires,considering key factors such as size(diameter),surface texture(roughness)and quantum size effects(phonon states)at different temperatures.For nanowires with a diameter of less than 20 nm,we highlight the importance of quantum size effects in heat capacity calculations,using dispersion relations derived from the modified frequency equation for the elasticity of a rod.The thermal conductivities of nanowires with diameters of 37,56,and 115nm are predicted using the Fuchs–Sondheimer model and Soffer’s specular parameter.Notably,the roughness parameters are chosen to reflect the technological characteristics of the real surfaces.Our findings reveal that surface texture plays a significant role in thermal conductivity,particularly in the realm of ballistic heat transfer within nanowires.This study provides practical recommendations for developing new thermal management materials.展开更多
Photosensors with versatile functionalities have emerged as a cornerstone for breakthroughs in the future optoelectronic systems across a wide range of applications.In particular,emerging photoelectrochemical(PEC)-typ...Photosensors with versatile functionalities have emerged as a cornerstone for breakthroughs in the future optoelectronic systems across a wide range of applications.In particular,emerging photoelectrochemical(PEC)-type devices have recently attracted extensive interest in liquid-based biosensing applications due to their natural electrolyte-assisted operating characteristics.Herein,a PEC-type photosensor was carefully designed and constructed by employing gallium nitride(GaN)p-n homojunction semiconductor nanowires on silicon,with the p-GaN segment strategically doped and then decorated with cobalt-nickel oxide(CoNiO_(x)).Essentially,the p-n homojunction configuration with facile p-doping engineering improves carrier separation efficiency and facilitates carrier transfer to the nanowire surface,while CoNiO_(x)decoration further boosts PEC reaction activity and carrier dynamics at the nanowire/electrolyte interface.Consequently,the constructed photosensor achieves a high responsivity of 247.8 mA W^(-1)while simultaneously exhibiting excellent operating stability.Strikingly,based on the remarkable stability and high responsivity of the device,a glucose sensing system was established with a demonstration of glucose level determination in real human serum.This work offers a feasible and universal approach in the pursuit of high-performance bio-related sensing applications via a rational design of PEC devices in the form of nanostructured architecture with strategic doping engineering.展开更多
GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nan...GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.展开更多
Nickel nanowires with large aspect ratio of up to 300 have been prepared by a hydrazine hydrate reduction method under applied magnetic field. The diameter of nickel nanowires is about 200 nm and length up to 60 μm. ...Nickel nanowires with large aspect ratio of up to 300 have been prepared by a hydrazine hydrate reduction method under applied magnetic field. The diameter of nickel nanowires is about 200 nm and length up to 60 μm. The role of magnetic field on the growth of magnetic nanowires is discussed and a magnetic nanowire growth mechanism has been proposed. Nickel ions are firstly reduced to nickel atoms by hydrazine hydrates in a strong alkaline solution and grow into tiny spherical nanoparticles. Then, these magnetic particles will align under a magnetic force and form linear chains. Furthermore, the as-formed chains can enhance the local magnetic field and attract other magnetic particles nearby, resulting finally as linear nanowires. The formation and the size of nanowires depend strongly on the magnitude of applied magnetic field.展开更多
GaN and AlN nanowires（NWs） have attracted great interests for the fabrication of novel nano-sized devices. In this paper, the nucleation processes of GaN and AlN NWs grown on Si substrates by molecular beam epitaxy...GaN and AlN nanowires（NWs） have attracted great interests for the fabrication of novel nano-sized devices. In this paper, the nucleation processes of GaN and AlN NWs grown on Si substrates by molecular beam epitaxy（MBE）are investigated. It is found that GaN NWs nucleated on in-situ formed Si3N4 fully release the stress upon the interface between GaN NW and amorphous Si3N4 layer, while AlN NWs nucleated by aluminization process gradually release the stress during growth. Depending on the strain status as well as the migration ability of Ⅲ group adatoms, the different growth kinetics of GaN and AlN NWs result in different NW morphologies, i.e., GaN NWs with uniform radii and AlN NWs with tapered bases.展开更多
This paper studies an oxide/silicon core/shell nanowire MOSFET （OS-CSNM）. Through three-dimensional device simulations, we have demonstrated that the OS-CSNM has a lower leakage current and higher Ion/Ioff ratio aft...This paper studies an oxide/silicon core/shell nanowire MOSFET （OS-CSNM）. Through three-dimensional device simulations, we have demonstrated that the OS-CSNM has a lower leakage current and higher Ion/Ioff ratio after intro- ducing the oxide core into a traditional nanowire MOSFET （TNM）. The oxide/silicon OS-CSNM structure suppresses threshold voltage roll-off, drain induced barrier lowering and subthreshold swing degradation. Smaller intrinsic device delay is also observed in OS-CSNM in comparison with that of TNM.展开更多
This paper presents an universal assembly approach,based on the oriented nanofibers,for the formation of large-scale ordered nanowire arrays.First,CdS NWs solution is dripped onto the substrate surface.Second,before t...This paper presents an universal assembly approach,based on the oriented nanofibers,for the formation of large-scale ordered nanowire arrays.First,CdS NWs solution is dripped onto the substrate surface.Second,before the CdS NWs solution evaporates,the oriented nanofibers slides along the substrate surface to assemble the CdS nanowires.The mechanism involving ordered alignment of nanowires on the substrate surface was investigated based on our experimental results.The resulting nanowires arrays can be further used for the creation of massive nanoelectronic-device arrays.展开更多
Transparent electrode based on silver nanowires(Ag NWs) emerges as an outstanding alternative of indium tin oxide film especially for flexible electronics. However, the conductivity of Ag NWs transparent electrode is ...Transparent electrode based on silver nanowires(Ag NWs) emerges as an outstanding alternative of indium tin oxide film especially for flexible electronics. However, the conductivity of Ag NWs transparent electrode is still dramatically limited by the contact resistance between nanowires at high transmittance. Polyvinylpyrrolidone(PVP) layer adsorbed on the nanowire surface acts as an electrically insulating barrier at wire–wire junctions, and some devastating post-treatment methods are proposed to reduce or eliminate PVP layer, which usually limit the application of the substrates susceptible to heat or pressure and burden the fabrication with high-cost, time-consuming, or inefficient processes. In this work, a simple and rapid pre-treatment washing method was proposed to reduce the thickness of PVP layer from 13.19 to0.96 nm and improve the contact between wires. Ag NW electrodes with sheet resistances of 15.6 and 204 X sq-1have been achieved at transmittances of 90 and 97.5 %, respectively. This method avoided any post-treatments and popularized the application of high-performance Ag NW transparent electrode on more substrates. The improved Ag NWs were successfully employed in a capacitive pressure sensor with high transparency, sensitivity, and reproducibility.展开更多
In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor depo...In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.展开更多
The development of advanced electrocatalysts for efficient catalyzing ethanol oxidation reaction(EOR)and oxygen reduction reaction(ORR) is significant for direct ethanol fuel cells(DEFCs).However,in many previous stud...The development of advanced electrocatalysts for efficient catalyzing ethanol oxidation reaction(EOR)and oxygen reduction reaction(ORR) is significant for direct ethanol fuel cells(DEFCs).However,in many previous studies,the major difficulties including lower utilization efficiency and weaker anti-CO-poison ability of Pt hamper the practical testing of such DEFCs,Herein,ternary Pt22Pd27C51 ultrathin(~5 nm)NWs are fabricated via a facile surfactant-free strategy.The surface and electronic structures of Pt22Pd27Cu51 NWs are further tailored via acid-etching treatment.The resulted PtPdCu NWs with an optimal atomic Pt/Pd/Cu ratio of 36:41:23 display excellent specific activities towards EOR(4.38 mA/cm^(2))and ORR(1.16 mA/cm^(2)),which are 19.8-and 5.7-folds larger than that of Pt/C,respectively.A singlecell was fabricated using Pt36Pd41Cu23 NWs as electrocatalyst in both anode and cathode with Pt loading of 1.2 mgpt/cm^(2).The power density measured at 80 ℃ is 21.7 mW/cm^(2),which is ~3.9 folds enhancement relative to that fabricated by using Pt/C(2 mgPt/cm^(2)).The enhanced catalytic performance of Pt36Pd41Cu23NWs could be attributed to that synergistic effect between Pt,Pd and Cu enhances CO anti-poisoning ability and promotes the C-C bond cleavage.This work provides a promising strategy for developing efficient electrocatalysts for DEFCs.展开更多
Direct electrochemical reduction of CO2 to multicarbon products is highly desirable, yet challenging. Here, we present a potentiostatic pulse-electrodeposition of high-aspect-ratio CuxAuy nanowire arrays (NWAs) as hig...Direct electrochemical reduction of CO2 to multicarbon products is highly desirable, yet challenging. Here, we present a potentiostatic pulse-electrodeposition of high-aspect-ratio CuxAuy nanowire arrays (NWAs) as high-performance electrocatalysts for the CO2 reduction reaction (CO2RR). The surface electronic structure related to the Cu:Au ratio in the CuxAuy NWAs could be facilely modulated by controlling the electrodeposition potential and the as-fabricated CuxAuy NWAs could be directly used as the catalytic electrode for the CO2RR. The morphology of the high-aspect-ratio nanowire array significantly lowers the onset potential of the alcohol formation due to the diffusion-induced enhancement of the local pH and CO concentration near the nanowire surface. Besides, the properly adjusted surface electronic structure of the CuxAuy NWA enables the adsorption of CO and facilitates the subsequent CO reduction to ethanol via the C-C coupling pathway. Owing to the synergistic effect of morphology and electronic structure, the optimized CuxAuy NWA selectively reduces CO2 to ethanol at low potentials of -0.5——0.7 V vs. RHE with a highest Faradaic efficiency of 48%. This work demonstrates the feasibility to optimize the activity and selectivity of the Cu-based electrocatalysts toward multicarbon alcohols for the CO2RR via simultaneous adjustment of the electronic structure and morphology of the catalysts.展开更多
Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activi...Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.展开更多
Optoelectronic characterisation of an individual ZnO nanowire in contact with a micro-grid template has been studied. The low-cost micro-grid template made by photolithography is used to fabricate the ohmic contact me...Optoelectronic characterisation of an individual ZnO nanowire in contact with a micro-grid template has been studied. The low-cost micro-grid template made by photolithography is used to fabricate the ohmic contact metal electrodes. The current increases linearly with the bias, indicating good ohmic contacts between the nanowire and the electrodes. The resistivity of the ZnO nanowire is calculated to be 3.8 Ω·cm. We investigate the photoresponses of an individual ZnO nanowire under different light illumination using light emitting diodes （λ= 505 nm, 460 nm, 375 nm） as excitation sources in atmosphere. When individual ZnO nanowire is exposured to different light irradiation, we find that it is extremely sensitive to UV illumination; the conductance is much larger upon UV illumination than that in the dark at room temperature. This phenomenon may be related to the surface oxygen molecule adsorbtion, which indicates their potential application to the optoelectronic switching device.展开更多
High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode...High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode assembly. The effects of carbon and ionomer contents on the electrode micro-structure and fuel cell performance are investigated by physical characterization and single cell testing. The Pt nanowires are gradient distributed across the cathode thickness, and more Pt exists near the membrane. Both the carbon and ionomer contents can affect the Pt nanowires distribution and aggregation. In addition, the carbon loading dominates the transport distance of gas and proton, and the ionomer content affects the triple phase boundaries and porosity in the cathode. The optimal structure of Pt nanowire cathode is obtained at 0.10 mg·cm^-2 carbon loading and 10 wt% ionomer.展开更多
基金supported by the Key Research and Development Program of Sichuan Province(Grant No.2023ZHCG0050)the Fundamental Research Funds for the Central Universities of China(Grant No.2682024QZ006 and 2682024ZTPY042)the Analytic and Testing Center of Southwest Jiaotong University.
文摘As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. U20A20227,62076208, and 62076207)Chongqing Talent Plan “Contract System” Project (Grant No. CQYC20210302257)+3 种基金National Key Laboratory of Smart Vehicle Safety Technology Open Fund Project (Grant No. IVSTSKL-202309)the Chongqing Technology Innovation and Application Development Special Major Project (Grant No. CSTB2023TIAD-STX0020)College of Artificial Intelligence, Southwest UniversityState Key Laboratory of Intelligent Vehicle Safety Technology
文摘Neuromorphic computing,inspired by the human brain,uses memristor devices for complex tasks.Recent studies show that self-organizing random nanowires can implement neuromorphic information processing,enabling data analysis.This paper presents a model based on these nanowire networks,with an improved conductance variation profile.We suggest using these networks for temporal information processing via a reservoir computing scheme and propose an efficient data encoding method using voltage pulses.The nanowire network layer generates dynamic behaviors for pulse voltages,allowing time series prediction analysis.Our experiment uses a double stochastic nanowire network architecture for processing multiple input signals,outperforming traditional reservoir computing in terms of fewer nodes,enriched dynamics and improved prediction accuracy.Experimental results confirm the high accuracy of this architecture on multiple real-time series datasets,making neuromorphic nanowire networks promising for physical implementation of reservoir computing.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.52130604 and 51825604)。
文摘Zinc oxide(ZnO)shows great potential in electronics,but its large intrinsic thermal conductivity limits its thermoelectric applications.In this work,we explore the significant carrier transport capacity and diameter-dependent thermoelectric characteristics of wurtzite-ZnO(0001)nanowires based on first-principles and molecular dynamics simulations.Under the synergistic effect of band degeneracy and weak phonon-electron scattering,P-type(ZnO)_(73) nanowires achieve an ultrahigh power factor above 1500μW·cm^(-1)·K^(-2)over a wide temperature range.The lattice thermal conductivity and carrier transport properties of ZnO nanowires exhibit a strong diameter size dependence.When the ZnO nanowire diameter exceeds 12.72A,the carrier transport properties increase significantly,while the thermal conductivity shows a slight increase with the diameter size,resulting in a ZT value of up to 6.4 at 700 K for P-type(ZnO)_(73).For the first time,the size effect is also illustrated by introducing two geometrical configurations of the ZnO nanowires.This work theoretically depicts the size optimization strategy for the thermoelectric conversion of ZnO nanowires.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.-RS-2024-00335976)。
文摘Electrochemical nitrate reduction(ENR)is an economical and eco-friendly method for converting industrial wastewater into valuable ammonia under atmospheric conditions.The main challenge lies in designing and developing highly durable ENR electrocatalysts.This study introduces defect-rich mesoporous CuO_(x) nanowires electrocatalyst synthesized using a novel solution-flame(sol-flame)hybrid method to control mesoporosity and introduce surface defects,thereby enhancing the electrochemical nitrate-toammonia production performance.We found surface defects(oxygen vacancies and Cu^(+))and unique mesoporous nanowire structure composed of tightly interconnected nanoparticles.The sol-flamesynthesized CuO_(x) nanowires(sf-CuO NWs)achieved superior ammonia yield rate(0.51 mmol h^(-1)cm^(-2)),faradaic efficiency(97.3%),and selectivity(86.2%)in 1 M KOH electrolyte(2000 ppm nitrate).This performance surpasses that of non-porous and less-defective CuO NWs and is attributed to the increased surface area and rapid electron transport facilitated by the distinctive morphology and generated defects.Theoretical calculation further suggests oxygen vacancies enhance NO_(3)^(-)adsorption on the sf-CuO NWs’surface and mitigate the competing hydrogen evolution reaction.This study outlines a strategic design and simple synthesis approach for nanowire electrocatalysts that boost the efficiency of electrochemical nitrate-to-ammonia conversion.
基金supported by Tsinghua University Initiative Scientific Research Programthe National Natural Science Foundation of China(Grant No.92065206)+1 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302400)the support from National Postdoctoral Researcher Program of China(Grant No.GZC20231368)。
文摘Semiconductor nanowires coupled to a superconductor provide a powerful testbed for quantum device physics such as Majorana zero modes and gate-tunable hybrid qubits.The performance of these quantum devices heavily relies on the quality of the induced superconducting gap.A hard gap.
基金supported by the Key Research and Development Program(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant Nos.62105267 and 62375225)+1 种基金the Shaanxi Fundamental Science Research Project for Mathematics and Physics(Grant No.22JSY004)Xi’an Science and Technology Plan Project(Grant No.2023JH-ZCGJ-0023)。
文摘Second harmonic generation(SHG)in optical materials serves as important techniques for laser source generations in awkward spectral ranges,physical identities of materials in crystalline symmetry and interfacial configuration.Here,we present a comprehensive review on SHGs in nanowires(NWs),which have been recognized as an important element in constructing photonic and optoelectronic devices with compact footprint and high quantum yield.Relying on NW’s one-dimensional geometry,its SHG could be employed as a sophisticated spectroscopy to determine the crystal phase and orientation,as well as the internal strain.The enhancements of SHG efficiency in NWs are discussed then,which were realized by hybrid integrating them with two-dimensional materials,nanophotonic and plasmonic structures.Finally,the potential applications of NW SHGs are concluded,including the areas of optical correlators and constructions of on-chip nano-laser sources.
基金financial support from the China Scholarship Council.
文摘We estimate the thermal properties of unsmooth Si nanowires,considering key factors such as size(diameter),surface texture(roughness)and quantum size effects(phonon states)at different temperatures.For nanowires with a diameter of less than 20 nm,we highlight the importance of quantum size effects in heat capacity calculations,using dispersion relations derived from the modified frequency equation for the elasticity of a rod.The thermal conductivities of nanowires with diameters of 37,56,and 115nm are predicted using the Fuchs–Sondheimer model and Soffer’s specular parameter.Notably,the roughness parameters are chosen to reflect the technological characteristics of the real surfaces.Our findings reveal that surface texture plays a significant role in thermal conductivity,particularly in the realm of ballistic heat transfer within nanowires.This study provides practical recommendations for developing new thermal management materials.
基金funded by the National Natural Science Foundation of China(Grant Nos.62322410,52272168,52161145404,81974530,and 82271721)the Fundamental Research Funds for the Central Universities(Grant No.WK3500000009)+1 种基金the International Projects of the Chinese Academy of Science(CAS)under Grant No.211134KYSB20210011Hubei Provincial Science and Technology Innovation Talents and Services Special Program(Grant No.2022EHB039)。
文摘Photosensors with versatile functionalities have emerged as a cornerstone for breakthroughs in the future optoelectronic systems across a wide range of applications.In particular,emerging photoelectrochemical(PEC)-type devices have recently attracted extensive interest in liquid-based biosensing applications due to their natural electrolyte-assisted operating characteristics.Herein,a PEC-type photosensor was carefully designed and constructed by employing gallium nitride(GaN)p-n homojunction semiconductor nanowires on silicon,with the p-GaN segment strategically doped and then decorated with cobalt-nickel oxide(CoNiO_(x)).Essentially,the p-n homojunction configuration with facile p-doping engineering improves carrier separation efficiency and facilitates carrier transfer to the nanowire surface,while CoNiO_(x)decoration further boosts PEC reaction activity and carrier dynamics at the nanowire/electrolyte interface.Consequently,the constructed photosensor achieves a high responsivity of 247.8 mA W^(-1)while simultaneously exhibiting excellent operating stability.Strikingly,based on the remarkable stability and high responsivity of the device,a glucose sensing system was established with a demonstration of glucose level determination in real human serum.This work offers a feasible and universal approach in the pursuit of high-performance bio-related sensing applications via a rational design of PEC devices in the form of nanostructured architecture with strategic doping engineering.
文摘GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.
基金supported by the Hi-Tech Research and Development Program of China(No.2007AA03Z300)Shanghai-Applied Materials Research and Development fund(No.07SA10)+3 种基金National Natural Science Foundation of China(No.50730008)Shanghai Science and Technology Grant(No:0752nm015,09ZR1414800,1052nm05500)National Basic Research Program of China(No.2006CB300406)the fund of Defence Key Laboratory of Nano/Micro Fabrication Technology
文摘Nickel nanowires with large aspect ratio of up to 300 have been prepared by a hydrazine hydrate reduction method under applied magnetic field. The diameter of nickel nanowires is about 200 nm and length up to 60 μm. The role of magnetic field on the growth of magnetic nanowires is discussed and a magnetic nanowire growth mechanism has been proposed. Nickel ions are firstly reduced to nickel atoms by hydrazine hydrates in a strong alkaline solution and grow into tiny spherical nanoparticles. Then, these magnetic particles will align under a magnetic force and form linear chains. Furthermore, the as-formed chains can enhance the local magnetic field and attract other magnetic particles nearby, resulting finally as linear nanowires. The formation and the size of nanowires depend strongly on the magnitude of applied magnetic field.
基金supported by the National Basic Research Program of China(Grant No.2013CB632804)the National Natural Science Foundation of China(Grant Nos.61176015,61176059,61210014,61321004,and 61307024)the High Technology Research and Development Program of China(Grant No.2012AA050601)
文摘GaN and AlN nanowires（NWs） have attracted great interests for the fabrication of novel nano-sized devices. In this paper, the nucleation processes of GaN and AlN NWs grown on Si substrates by molecular beam epitaxy（MBE）are investigated. It is found that GaN NWs nucleated on in-situ formed Si3N4 fully release the stress upon the interface between GaN NW and amorphous Si3N4 layer, while AlN NWs nucleated by aluminization process gradually release the stress during growth. Depending on the strain status as well as the migration ability of Ⅲ group adatoms, the different growth kinetics of GaN and AlN NWs result in different NW morphologies, i.e., GaN NWs with uniform radii and AlN NWs with tapered bases.
基金Project supported by National Natural Science Foundation of China (Grant No. 60876027)Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200800010054)
文摘This paper studies an oxide/silicon core/shell nanowire MOSFET （OS-CSNM）. Through three-dimensional device simulations, we have demonstrated that the OS-CSNM has a lower leakage current and higher Ion/Ioff ratio after intro- ducing the oxide core into a traditional nanowire MOSFET （TNM）. The oxide/silicon OS-CSNM structure suppresses threshold voltage roll-off, drain induced barrier lowering and subthreshold swing degradation. Smaller intrinsic device delay is also observed in OS-CSNM in comparison with that of TNM.
基金supported by the Scientific Research Foundation of Nanjing University of Posts and Telecommunications(NY210083,NY209027)
文摘This paper presents an universal assembly approach,based on the oriented nanofibers,for the formation of large-scale ordered nanowire arrays.First,CdS NWs solution is dripped onto the substrate surface.Second,before the CdS NWs solution evaporates,the oriented nanofibers slides along the substrate surface to assemble the CdS nanowires.The mechanism involving ordered alignment of nanowires on the substrate surface was investigated based on our experimental results.The resulting nanowires arrays can be further used for the creation of massive nanoelectronic-device arrays.
基金partly supported by Showa Denko Co. Ltd, Grant-in-Aid for Scientific Research (Kaken S, 24226017)COI Stream Projectfinancial support from China Scholarship Council
文摘Transparent electrode based on silver nanowires(Ag NWs) emerges as an outstanding alternative of indium tin oxide film especially for flexible electronics. However, the conductivity of Ag NWs transparent electrode is still dramatically limited by the contact resistance between nanowires at high transmittance. Polyvinylpyrrolidone(PVP) layer adsorbed on the nanowire surface acts as an electrically insulating barrier at wire–wire junctions, and some devastating post-treatment methods are proposed to reduce or eliminate PVP layer, which usually limit the application of the substrates susceptible to heat or pressure and burden the fabrication with high-cost, time-consuming, or inefficient processes. In this work, a simple and rapid pre-treatment washing method was proposed to reduce the thickness of PVP layer from 13.19 to0.96 nm and improve the contact between wires. Ag NW electrodes with sheet resistances of 15.6 and 204 X sq-1have been achieved at transmittances of 90 and 97.5 %, respectively. This method avoided any post-treatments and popularized the application of high-performance Ag NW transparent electrode on more substrates. The improved Ag NWs were successfully employed in a capacitive pressure sensor with high transparency, sensitivity, and reproducibility.
基金the NSF of China(Nos.61574054,61505051,11374092,11204073,61474040,and51302077)the National Basic Research Program of China(No.2012CB932703)+2 种基金the Hunan province science and technology plan(No.2014FJ2001,2014GK3015,and 2014TT1004)the Hunan Provincial Natural Science Foundation of China(No.2015JJ3049)the Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
文摘In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.
基金supported by the National Natural Science Foundation of China (No. 21902119)。
文摘The development of advanced electrocatalysts for efficient catalyzing ethanol oxidation reaction(EOR)and oxygen reduction reaction(ORR) is significant for direct ethanol fuel cells(DEFCs).However,in many previous studies,the major difficulties including lower utilization efficiency and weaker anti-CO-poison ability of Pt hamper the practical testing of such DEFCs,Herein,ternary Pt22Pd27C51 ultrathin(~5 nm)NWs are fabricated via a facile surfactant-free strategy.The surface and electronic structures of Pt22Pd27Cu51 NWs are further tailored via acid-etching treatment.The resulted PtPdCu NWs with an optimal atomic Pt/Pd/Cu ratio of 36:41:23 display excellent specific activities towards EOR(4.38 mA/cm^(2))and ORR(1.16 mA/cm^(2)),which are 19.8-and 5.7-folds larger than that of Pt/C,respectively.A singlecell was fabricated using Pt36Pd41Cu23 NWs as electrocatalyst in both anode and cathode with Pt loading of 1.2 mgpt/cm^(2).The power density measured at 80 ℃ is 21.7 mW/cm^(2),which is ~3.9 folds enhancement relative to that fabricated by using Pt/C(2 mgPt/cm^(2)).The enhanced catalytic performance of Pt36Pd41Cu23NWs could be attributed to that synergistic effect between Pt,Pd and Cu enhances CO anti-poisoning ability and promotes the C-C bond cleavage.This work provides a promising strategy for developing efficient electrocatalysts for DEFCs.
基金supported by the Natural Science Foundation of Hunan Province (grant no. 2018JJ2485)Hunan Provincial Science and Technology Plan Project (grant nos. 2018RS3008 and 2017TP1001)+1 种基金the National Natural Science Foundation of China (grant no. 21872174)Innovation-Driven Project of Central South University (grant nos. 2016CXS031 and 2017CX003)
文摘Direct electrochemical reduction of CO2 to multicarbon products is highly desirable, yet challenging. Here, we present a potentiostatic pulse-electrodeposition of high-aspect-ratio CuxAuy nanowire arrays (NWAs) as high-performance electrocatalysts for the CO2 reduction reaction (CO2RR). The surface electronic structure related to the Cu:Au ratio in the CuxAuy NWAs could be facilely modulated by controlling the electrodeposition potential and the as-fabricated CuxAuy NWAs could be directly used as the catalytic electrode for the CO2RR. The morphology of the high-aspect-ratio nanowire array significantly lowers the onset potential of the alcohol formation due to the diffusion-induced enhancement of the local pH and CO concentration near the nanowire surface. Besides, the properly adjusted surface electronic structure of the CuxAuy NWA enables the adsorption of CO and facilitates the subsequent CO reduction to ethanol via the C-C coupling pathway. Owing to the synergistic effect of morphology and electronic structure, the optimized CuxAuy NWA selectively reduces CO2 to ethanol at low potentials of -0.5——0.7 V vs. RHE with a highest Faradaic efficiency of 48%. This work demonstrates the feasibility to optimize the activity and selectivity of the Cu-based electrocatalysts toward multicarbon alcohols for the CO2RR via simultaneous adjustment of the electronic structure and morphology of the catalysts.
基金supported by the National Natural Science Foundation of China(51873100)Natural Science Foundation of Shaanxi Province(2020JZ-23)+2 种基金the Fundamental Research Funds for the Central Universities(GK202101005 and 2021CBLZ004)the Innovation Team Project for Graduate Student at Shaanxi Normal University(TD2020048Y)the 111 Project(B14041)。
文摘Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.
基金supported by the National Natural Science Foundation of China (Grant Nso. 60776010,60940021 and 11074060)the Natural Science Foundation of Heilongjiang Province,China (Grant No. A2008-07)the Doctoral Start-up Fund of Harbin Normal University,China
文摘Optoelectronic characterisation of an individual ZnO nanowire in contact with a micro-grid template has been studied. The low-cost micro-grid template made by photolithography is used to fabricate the ohmic contact metal electrodes. The current increases linearly with the bias, indicating good ohmic contacts between the nanowire and the electrodes. The resistivity of the ZnO nanowire is calculated to be 3.8 Ω·cm. We investigate the photoresponses of an individual ZnO nanowire under different light illumination using light emitting diodes （λ= 505 nm, 460 nm, 375 nm） as excitation sources in atmosphere. When individual ZnO nanowire is exposured to different light irradiation, we find that it is extremely sensitive to UV illumination; the conductance is much larger upon UV illumination than that in the dark at room temperature. This phenomenon may be related to the surface oxygen molecule adsorbtion, which indicates their potential application to the optoelectronic switching device.
文摘High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode assembly. The effects of carbon and ionomer contents on the electrode micro-structure and fuel cell performance are investigated by physical characterization and single cell testing. The Pt nanowires are gradient distributed across the cathode thickness, and more Pt exists near the membrane. Both the carbon and ionomer contents can affect the Pt nanowires distribution and aggregation. In addition, the carbon loading dominates the transport distance of gas and proton, and the ionomer content affects the triple phase boundaries and porosity in the cathode. The optimal structure of Pt nanowire cathode is obtained at 0.10 mg·cm^-2 carbon loading and 10 wt% ionomer.
