Ever since discovery of graphene,two-dimensional(2D)materials become a new tool box for information technology.Among the 2D family,ultrathin bismuth(Bi)has attracted a great deal of attention in recent years due to it...Ever since discovery of graphene,two-dimensional(2D)materials become a new tool box for information technology.Among the 2D family,ultrathin bismuth(Bi)has attracted a great deal of attention in recent years due to its unique topological insulating properties and large magnetoresistance.However,the scalable synthesis of layered Bi ultrathin films is rarely been reported,which would greatly restrict further fundamental investigation and practical device development.Here,we demonstrate the direct growth of homogeneous and centimeter-scale layered Bi films by pulsed laser deposition(PLD)technique.The as-grown Bi film exhibits high-purity phase and good crystallinity.In addition,both(111)and(110)-oriented Bi films can be synthesized by precisely controlling the processing temperature.The characterization of optical properties shows a thickness dependent band gaps(0.075-0.2 eV).Moreover,Bi thin-film-based field-effect transistors have been demonstrated,exhibiting a large carrier mobility of 220 cm2 V−1 s−1.Our work suggests that the PLD-grown Bi films would hold the potential to develop spintronic applications,electronic and optoelectronic devices used for information science and technology.展开更多
Cr-coated zirconium alloy was prepared by pulsed laser deposition(PLD)for the application of accident-tolerant fuel cladding in light water reactors.The microstructural characteristics of the Cr coating and its evolut...Cr-coated zirconium alloy was prepared by pulsed laser deposition(PLD)for the application of accident-tolerant fuel cladding in light water reactors.The microstructural characteristics of the Cr coating and its evolution with temperature were investigated using grazing incidence X-ray diff raction and in situ heating transmission electron microscopy(TEM).Results show that the microstructure of the laser-deposited Cr coatings consists mainly of fine and non-specific shaped nano-crystals in the inner layer and columnar crystals in the outer layer.The recrystallization of the Cr-coating layer starts at 300–400℃ to release the high strain introduced by PLD,and the grain coalescence starts at temperatures>400°C.Upon annealing,the(110)-texture gradually intensifi es because of its high reticular density and low close-packed energy.Additionally,in situ heating TEM observation shows the presence of cavities on the Cr–Zr interface,which may result from the interdiff usion and/or the transformation from amorphous to crystalline.展开更多
Conventional charging methods for lithium-ion battery(LIB)are challenged with vital problems at low temperatures:risk of lithium(Li)plating and low charging speed.This study proposes a fast-charging strategy without L...Conventional charging methods for lithium-ion battery(LIB)are challenged with vital problems at low temperatures:risk of lithium(Li)plating and low charging speed.This study proposes a fast-charging strategy without Li plating to achieve high-rate charging at low temperatures with bidirectional chargers.The strategy combines the pulsed-heating method and the optimal charging method via precise control of the battery states.A thermo-electric coupled model is developed based on the pseudo-twodimensional(P2D)electrochemical model to derive charging performances.Two current maps of pulsed heating and charging are generated to realize real-time control.Therefore,our proposed strategy achieves a 3 C equivalent rate at 0℃ and 1.5 C at-10℃ without Li plating,which is 10–30 times faster than the traditional methods.The entropy method is employed to balance the charging speed and the energy efficiency,and the charging performance is further enhanced.For practical application,the power limitation of the charger is considered,and a 2.4 C equivalent rate is achieved at 0℃ with a 250 kW maximum power output.This novel strategy significantly expands LIB usage boundary,and increases charging speed and battery safety.展开更多
Polycrystalline ZnS films were prepared by pulsed laser deposition （PLD） on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 ℃, which is a suita...Polycrystalline ZnS films were prepared by pulsed laser deposition （PLD） on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 ℃, which is a suitable alternative to chemical bath deposited （CBD） CdS as a buffer layer in Cu（In,Ga）Se2 （CIGS） solar cells. X-ray diffraction studies indicate the films are polycrystalline with zinc-blende structure and they exhibit preferential orientation along the cubic phase β-ZnS （111） direction, which conflicts with the conclusion of wurtzite structure by Murali that the ZnS films deposited by pulse plating technique was polycrystalline with wurtzite structure. The Raman spectra of grown films show Al mode at approximately 350 cm^-1, generally observed in the cubic phase β-ZnS compounds. The planar and the cross-sectional morphology were observed by scanning electron microscopic. The dense, smooth, uniform grains are formed on the quartz glass substrates through PLD technique. The grain size of ZnS deposited by PLD is much smaller than that of CdS by conventional CBD method, which is analyzed as the main reason of detrimental cell performance. The composition of the ZnS films was also measured by X-ray fluorescence. The typical ZnS films obtained in this work are near stoichiometric and only a small amount of S-rich. The energy band gaps at different temperatures were obtained by absorption spectroscopy measurement, which increases from 3.2 eV to 3.7 eV with the increasing of the deposition temperature. ZnS has a wider energy band gap than CdS （2.4 eV）, which can enhance the blue response of the photovoltaic cells. These results show the high-quality of these substitute buffer layer materials are prepared through an all-dry technology, which can be used in the manufacture of CIGS thin film solar cells.展开更多
Developing novel lead-free ferroelectric materials is crucial for next-generationmicroelectronic technologies that are energy efficient and environmentfriendly.However,materials discovery and property optimization are...Developing novel lead-free ferroelectric materials is crucial for next-generationmicroelectronic technologies that are energy efficient and environmentfriendly.However,materials discovery and property optimization are typicallytime-consuming due to the limited throughput of traditional synthesismethods.In this work,we use a high-throughput combinatorial synthesisapproach to fabricate lead-free ferroelectric superlattices and solid solutions of(Ba_(0.7)Ca_(0.3))TiO_(3)(BCT)and Ba(Zr_(0.2)Ti_(0.8))O_(3)(BZT)phases with continuous variationof composition and layer thickness.High-resolution x-ray diffraction(XRD)and analytical scanning transmission electron microscopy(STEM)demonstratehigh film quality and well-controlled compositional gradients.Ferroelectricand dielectric property measurements identify the“optimal propertypoint”achieved at the composition of 48BZT–52BCT.Displacement vectormaps reveal that ferroelectric domain sizes are tunable by varying{BCT–BZT}Nsuperlattice geometry.This high-throughput synthesis approach can be appliedto many other material systems to expedite new materials discovery and properties optimization,allowing for the exploration of a large area of phasespace within a single growth.展开更多
Functional van der Waals(vdWs)heterostructures based on layered materials have shown tremendous potential in next-generation optoelectronic devices.To date,numerous vdWs heterostructures have been investigated based o...Functional van der Waals(vdWs)heterostructures based on layered materials have shown tremendous potential in next-generation optoelectronic devices.To date,numerous vdWs heterostructures have been investigated based on stacking or epitaxial growth technology.However the complicated synthesis process greatly limits the large-scale integration of the heterostructure device array,which is essential for practical applications.Here,a planar photodetector array with an out-of-plane vertical In2Se3/SnSe2heterostructure as the photosensitive channel was self-assembled through a pulsed laser deposition(PLD)technique.The vertical built-in field was exploited to suppress the dark current and separate the photogenerated carriers.The realized devices possess an ultralow dark current of 6.3 p A,combined with a high detectivity of 8.8×1011Jones and a high signal-to-noise ratio(SNR)beyond 3×104.These performance metrics not only are one order of magnitude superior to pure In2Se3device,but also demonstrate the unique advantage of detecting weak signals.In addition,this heterostructure photodetector array can further be constructed on flexible polyimide(PI)substrate.These flexible devices also demonstrate effective light detection capability and the photoresponse remains unchanged even after 200 cycles of bending.These findings pave a way toward the development of next-generation large area and high integration optoelectronic technologies.展开更多
Arc deposition, a widely used surface coating technique, has disadvantages such as large droplet size and high deposition temperature. Recent trend in its renovation is the introduction of pulsed bias at the. substrat...Arc deposition, a widely used surface coating technique, has disadvantages such as large droplet size and high deposition temperature. Recent trend in its renovation is the introduction of pulsed bias at the. substrate. The present paper attempts to describe the deposition process of TiN films using this technique with emphasis laid on the understanding of the basic problems such as discharge plasma properties, temperature calculation, and droplet size reduction. We show that this technique improves the film micro structure and quality, lowers deposition temperature, and allows coatings on insulating substrates. After analyzing load current oscillation behaviors, we have determined that the plasma load is of capacitance nature due to plasma sheath and that it is equivalent to a circuit element consisting of parallel capacitance and resistance. At last, we point out the remaining problems and future development of the pulsed-bias arc deposition technique.展开更多
An ablation model of targets irradiated by pulsed laser is established. By using the simple energy balance conditions, the relationship between ablation surface location and time is derived. By an adiabatic approximat...An ablation model of targets irradiated by pulsed laser is established. By using the simple energy balance conditions, the relationship between ablation surface location and time is derived. By an adiabatic approximation, the continuous-temperature condition, energy conservation and all boundary conditions can be established. By applying the analytical method and integral-approximation method, the solid and liquid phase temperature distributions are obtained and found to be a function of time and location. The interface of solid and liquid phase is also derived. The results are compared with the other published data. In addition, the dynamics process of pulsed laser deposition of KTN (Kta0.65Nb0.35O3) thin film is simulated in detail by using fluid dynamics theory. By combining the expression of the target ablation ratio and the dynamic equation and by using the experimental data, the effects of laser action parameters on the thickness distribution of thin film and on the thin film component characteristics are discussed. The results are in good agreement with the experimental data.展开更多
Advances in energy conversion and storage technologies,such as water electrolyzers,rechargeable metal-air batteries,and fuel cells,have enabled a renewable and sustainable future.The efficiency and effectiveness of th...Advances in energy conversion and storage technologies,such as water electrolyzers,rechargeable metal-air batteries,and fuel cells,have enabled a renewable and sustainable future.The efficiency and effectiveness of these technologies largely relies on the physicochemical properties of the functional materials used,specifically electrocatalysts.Pulsed laser deposition(PLD)is a powerful technique for the synthesis of thin film materials,offering a unique platform for understanding electrochemical reaction mechanisms and searching for low-cost and high-performance electrocatalysts.In this mini-review,we present the latest studies in which thin film materials(mainly focused on perovskite oxide thin films)via PLD have been actively utilized in the field of electrocatalysis.The fundamentals and advantages of PLD in the synthesis of thin films are discussed first.Then,emerging types of thin films associated with electrochemical applications are presented.Special emphasis is placed on material design methods to reveal the reaction mechanisms and establish the structure–performance relationships by understanding structural variations in precatalysts and surface reconstruction under reaction conditions.Finally,we discuss remaining challenges and future perspectives.展开更多
Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effect...Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings,owing to their combination of various properties that are essential for bio-implants,such as osteointegration and antibacterial character.In the present study,thin hopeite coatings were produced by Pulsed laser deposition(PLD)and radio frequency magnetron sputtering(RFMS)on Ti64 substrates.The obtained hopeite coatings were annealed at 500°C in ambient air and studied in terms of surface morphology,phase composition,surface roughness,adhesion strength,antibacterial efficacy,apatite forming ability,and surface wettability by scanning electron microscope(SEM),X-ray diffraction(XRD),atomic force microscope(AFM),tensometer,fluorescence-activated cell sorting(FACS),simulated body fluid(SBF)immersion test and contact angle goniometer,respectively.Furthermore,based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates,provides effective alternatives to conventional coatings,largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.展开更多
ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectropho...ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer. The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains three components with λ=508 nm, 554 nm and 698 nm. The origin and possible mechanism of the visible PL are discussed, and they can be attributed to the PL recombination of ZnO and DLC thin films.展开更多
ZnO/diamond-like carbon(DLC)thin films are deposited by pulsed laser deposition(PLD),and the room-temperature photoluminescence(PL)is investigated.Using a fluorescence spectrophotometer,we obtain the PL spectra of DLC...ZnO/diamond-like carbon(DLC)thin films are deposited by pulsed laser deposition(PLD),and the room-temperature photoluminescence(PL)is investigated.Using a fluorescence spectrophotometer,we obtain the PL spectra of DLC/Si and ZnO/Si thin films deposited at different substrate temperatures.The ZnO/DLC thin films show a broadband emission almost containing the entire visible spectrum.The Gaussian fitting curves of PL spectra reveal that the visible emission of ZnO/DLC thin films consists of three peaks centered at 381 nm,526 nm and 682 nm,which are attributed to the radiative recombination of ZnO and DLC,respectively.The Commission International de l,Eclairage(CIE)1931(x,y)chromaticity space of ZnO/DLC thin films indicates that the visible PL spectrum is very close to the standard white-light region.展开更多
Cu bump was transferred using a focused laser pulse for microelectronic packaging.An Nd:YAG laser pulse (maximum energy of 500 mJ;wavelength of 1064 nm;fluences of 0.4-2.1 kJ/cm2) was irradiated on a sacrificial absor...Cu bump was transferred using a focused laser pulse for microelectronic packaging.An Nd:YAG laser pulse (maximum energy of 500 mJ;wavelength of 1064 nm;fluences of 0.4-2.1 kJ/cm2) was irradiated on a sacrificial absorption layer with copper coating.The focused laser beam induced plasma between the semi-transparent donor slide and the sacrificial layer,causing a shock wave.The shock wave pressure pushed the Cu layer and transferred material to deposit a bump on substrate.A beam-shaper was used to produce uniform pressure at the interface to reduce fragmentation of the transferred material on the substrate.The calculated shock wave pressure with respect to laser fluence was 1-3 GPa.A Cu bump of diameter of 200 μm was successfully deposited at laser fluence of 0.6 kJ/cm 2.The pressure control at the sacrificial layer using a laser pulse was critical to produce a bump with less fragmentation.The technique can be applied to forming Cu bump for an interconnecting process in electronics.展开更多
A high-throughput multi-plume pulsed-laser deposition （MPPLD） system has been demonstrated and compared to previous techniques. Whereas most combinatorial pulsedlaser deposition （PLD） systems have focused on achie...A high-throughput multi-plume pulsed-laser deposition （MPPLD） system has been demonstrated and compared to previous techniques. Whereas most combinatorial pulsedlaser deposition （PLD） systems have focused on achieving thickness uniformity using sequential multilayer deposition and masking followed by post-deposition annealing, MPPLD directly deposits a compositionally varied library of compounds using the directionality of PLD plumes and the resulting spatial variations of deposition rate. This system is more suitable for high-throughput compound thin-film fabrication.展开更多
TiO2 thin films were prepared on glass substrates using the PLD (Pulsed Laser Deposition) technique. In order to carry out the ablation process, a Nd:YAG laser was used emitting in 1064 nm wavelength at 10 Hz repetiti...TiO2 thin films were prepared on glass substrates using the PLD (Pulsed Laser Deposition) technique. In order to carry out the ablation process, a Nd:YAG laser was used emitting in 1064 nm wavelength at 10 Hz repetition rate, set up for operating in both single-pulse and multi-pulse regimes. A comparison of the deposition rate, the optical and morphological properties of the layers obtained from both ablation regimes was made, which showed that the multi-pulsed ablation produced layers with a higher surface quality and better optical properties.展开更多
In this work,we have successfully grown high quality epitaxialβ-Ga_(2)O_(3)thin films onβ-Ga_(2)O_(3)(100)and Al_(2)O_(3)(0001)substrates using pulsed laser deposition(PLD).By optimizing temperature and oxygen press...In this work,we have successfully grown high quality epitaxialβ-Ga_(2)O_(3)thin films onβ-Ga_(2)O_(3)(100)and Al_(2)O_(3)(0001)substrates using pulsed laser deposition(PLD).By optimizing temperature and oxygen pressure,the best conditions were found to be 650-700℃and 0.5 Pa.To further improve the quality of hetero-epitaxialβ-Ga_(2)O_(3),the sapphire substrates were pretreated for atomic terraced surface by chemical cleaning and high temperature annealing.From the optical transmittance measurements,the films grown at 600-750℃exhibit a clear absorption edge at deep ultraviolet region around 250-275 nm wavelength.High resolution transmission electron microscope(HRTEM)images and X-ray diffraction(XRD)patterns demonstrate thatβ-Ga_(2)O_(3)(-201)//Al_(2)O_(3)(0001)epitaxial texture dominated the epitaxial oxide films on sapphire substrate,which opens up the possibilities of high power electric devices.展开更多
基金This work was supported by the grants from Research Grants Council of Hong Kong CRF No.C7036-17WGRF No.PolyU 153033/17PPolyU Grant No.G-UABC.
文摘Ever since discovery of graphene,two-dimensional(2D)materials become a new tool box for information technology.Among the 2D family,ultrathin bismuth(Bi)has attracted a great deal of attention in recent years due to its unique topological insulating properties and large magnetoresistance.However,the scalable synthesis of layered Bi ultrathin films is rarely been reported,which would greatly restrict further fundamental investigation and practical device development.Here,we demonstrate the direct growth of homogeneous and centimeter-scale layered Bi films by pulsed laser deposition(PLD)technique.The as-grown Bi film exhibits high-purity phase and good crystallinity.In addition,both(111)and(110)-oriented Bi films can be synthesized by precisely controlling the processing temperature.The characterization of optical properties shows a thickness dependent band gaps(0.075-0.2 eV).Moreover,Bi thin-film-based field-effect transistors have been demonstrated,exhibiting a large carrier mobility of 220 cm2 V−1 s−1.Our work suggests that the PLD-grown Bi films would hold the potential to develop spintronic applications,electronic and optoelectronic devices used for information science and technology.
基金supported by the Ministry of Education,Culture,Sport,Science and Technology of Japan(MEXT)Innovative Nuclear Research and Development Program(Grant No.JPMXD0220354500)Japan Atomic Energy Agency(JAEA)Nuclear Energy S&T and Human Resource Development Project through Concentrating Wisdom(Grant No.JPJA20P20337528)+1 种基金the Collaborative Research Project at the Nuclear Professional School,School of Engineering,the University of Tokyothe continuous support from the China Scholarship Council(CSC)。
文摘Cr-coated zirconium alloy was prepared by pulsed laser deposition(PLD)for the application of accident-tolerant fuel cladding in light water reactors.The microstructural characteristics of the Cr coating and its evolution with temperature were investigated using grazing incidence X-ray diff raction and in situ heating transmission electron microscopy(TEM).Results show that the microstructure of the laser-deposited Cr coatings consists mainly of fine and non-specific shaped nano-crystals in the inner layer and columnar crystals in the outer layer.The recrystallization of the Cr-coating layer starts at 300–400℃ to release the high strain introduced by PLD,and the grain coalescence starts at temperatures>400°C.Upon annealing,the(110)-texture gradually intensifi es because of its high reticular density and low close-packed energy.Additionally,in situ heating TEM observation shows the presence of cavities on the Cr–Zr interface,which may result from the interdiff usion and/or the transformation from amorphous to crystalline.
基金supported by the National Natural Science Foundation of China(52177217 and 52037006)the Beijing Natural Science Foundation(3212031)。
文摘Conventional charging methods for lithium-ion battery(LIB)are challenged with vital problems at low temperatures:risk of lithium(Li)plating and low charging speed.This study proposes a fast-charging strategy without Li plating to achieve high-rate charging at low temperatures with bidirectional chargers.The strategy combines the pulsed-heating method and the optimal charging method via precise control of the battery states.A thermo-electric coupled model is developed based on the pseudo-twodimensional(P2D)electrochemical model to derive charging performances.Two current maps of pulsed heating and charging are generated to realize real-time control.Therefore,our proposed strategy achieves a 3 C equivalent rate at 0℃ and 1.5 C at-10℃ without Li plating,which is 10–30 times faster than the traditional methods.The entropy method is employed to balance the charging speed and the energy efficiency,and the charging performance is further enhanced.For practical application,the power limitation of the charger is considered,and a 2.4 C equivalent rate is achieved at 0℃ with a 250 kW maximum power output.This novel strategy significantly expands LIB usage boundary,and increases charging speed and battery safety.
基金ACKNOWLEDGMENTS This work was supported by the National Basic Research Program of China （No.2006CB92200） and the National Natural Science Foundation of China （No.10774136）.
文摘Polycrystalline ZnS films were prepared by pulsed laser deposition （PLD） on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 ℃, which is a suitable alternative to chemical bath deposited （CBD） CdS as a buffer layer in Cu（In,Ga）Se2 （CIGS） solar cells. X-ray diffraction studies indicate the films are polycrystalline with zinc-blende structure and they exhibit preferential orientation along the cubic phase β-ZnS （111） direction, which conflicts with the conclusion of wurtzite structure by Murali that the ZnS films deposited by pulse plating technique was polycrystalline with wurtzite structure. The Raman spectra of grown films show Al mode at approximately 350 cm^-1, generally observed in the cubic phase β-ZnS compounds. The planar and the cross-sectional morphology were observed by scanning electron microscopic. The dense, smooth, uniform grains are formed on the quartz glass substrates through PLD technique. The grain size of ZnS deposited by PLD is much smaller than that of CdS by conventional CBD method, which is analyzed as the main reason of detrimental cell performance. The composition of the ZnS films was also measured by X-ray fluorescence. The typical ZnS films obtained in this work are near stoichiometric and only a small amount of S-rich. The energy band gaps at different temperatures were obtained by absorption spectroscopy measurement, which increases from 3.2 eV to 3.7 eV with the increasing of the deposition temperature. ZnS has a wider energy band gap than CdS （2.4 eV）, which can enhance the blue response of the photovoltaic cells. These results show the high-quality of these substitute buffer layer materials are prepared through an all-dry technology, which can be used in the manufacture of CIGS thin film solar cells.
基金NNSA's Laboratory Directed Research andDevelopment ProgramCenter forIntegrated Nanotechnologies,an Office ofScience User Facility operated for theU.S.Department of Energy(DOE)Officeof Science by Los Alamos NationalLaboratory,Grant/Award Number:89233218CNA000001+5 种基金Sandia NationalLaboratories,Grant/Award Number:DENA0003525U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Science and EngineeringDivisionArgonne National LaboratoryU.S.DOE Office of Science-Basic Energy Sciences,Grant/Award Number:DEAC02-06CH11357Center for NanophaseMaterials SciencesACS PetroleumResearch Fund under Doctoral NewInvestigator Grant,Grant/Award Number:62603-DNI10。
文摘Developing novel lead-free ferroelectric materials is crucial for next-generationmicroelectronic technologies that are energy efficient and environmentfriendly.However,materials discovery and property optimization are typicallytime-consuming due to the limited throughput of traditional synthesismethods.In this work,we use a high-throughput combinatorial synthesisapproach to fabricate lead-free ferroelectric superlattices and solid solutions of(Ba_(0.7)Ca_(0.3))TiO_(3)(BCT)and Ba(Zr_(0.2)Ti_(0.8))O_(3)(BZT)phases with continuous variationof composition and layer thickness.High-resolution x-ray diffraction(XRD)and analytical scanning transmission electron microscopy(STEM)demonstratehigh film quality and well-controlled compositional gradients.Ferroelectricand dielectric property measurements identify the“optimal propertypoint”achieved at the composition of 48BZT–52BCT.Displacement vectormaps reveal that ferroelectric domain sizes are tunable by varying{BCT–BZT}Nsuperlattice geometry.This high-throughput synthesis approach can be appliedto many other material systems to expedite new materials discovery and properties optimization,allowing for the exploration of a large area of phasespace within a single growth.
基金supported by the National Natural Science Foundation of China(61805044 and 11674310)the Key Platforms and Research Projects of Department of Education of Guangdong Province(2018KTSCX050)“The Pearl River Talent Recruitment Program”。
文摘Functional van der Waals(vdWs)heterostructures based on layered materials have shown tremendous potential in next-generation optoelectronic devices.To date,numerous vdWs heterostructures have been investigated based on stacking or epitaxial growth technology.However the complicated synthesis process greatly limits the large-scale integration of the heterostructure device array,which is essential for practical applications.Here,a planar photodetector array with an out-of-plane vertical In2Se3/SnSe2heterostructure as the photosensitive channel was self-assembled through a pulsed laser deposition(PLD)technique.The vertical built-in field was exploited to suppress the dark current and separate the photogenerated carriers.The realized devices possess an ultralow dark current of 6.3 p A,combined with a high detectivity of 8.8×1011Jones and a high signal-to-noise ratio(SNR)beyond 3×104.These performance metrics not only are one order of magnitude superior to pure In2Se3device,but also demonstrate the unique advantage of detecting weak signals.In addition,this heterostructure photodetector array can further be constructed on flexible polyimide(PI)substrate.These flexible devices also demonstrate effective light detection capability and the photoresponse remains unchanged even after 200 cycles of bending.These findings pave a way toward the development of next-generation large area and high integration optoelectronic technologies.
基金This work was supported by the National Natural Science Foundation of China (Grant No.50071017).
文摘Arc deposition, a widely used surface coating technique, has disadvantages such as large droplet size and high deposition temperature. Recent trend in its renovation is the introduction of pulsed bias at the. substrate. The present paper attempts to describe the deposition process of TiN films using this technique with emphasis laid on the understanding of the basic problems such as discharge plasma properties, temperature calculation, and droplet size reduction. We show that this technique improves the film micro structure and quality, lowers deposition temperature, and allows coatings on insulating substrates. After analyzing load current oscillation behaviors, we have determined that the plasma load is of capacitance nature due to plasma sheath and that it is equivalent to a circuit element consisting of parallel capacitance and resistance. At last, we point out the remaining problems and future development of the pulsed-bias arc deposition technique.
文摘An ablation model of targets irradiated by pulsed laser is established. By using the simple energy balance conditions, the relationship between ablation surface location and time is derived. By an adiabatic approximation, the continuous-temperature condition, energy conservation and all boundary conditions can be established. By applying the analytical method and integral-approximation method, the solid and liquid phase temperature distributions are obtained and found to be a function of time and location. The interface of solid and liquid phase is also derived. The results are compared with the other published data. In addition, the dynamics process of pulsed laser deposition of KTN (Kta0.65Nb0.35O3) thin film is simulated in detail by using fluid dynamics theory. By combining the expression of the target ablation ratio and the dynamic equation and by using the experimental data, the effects of laser action parameters on the thickness distribution of thin film and on the thin film component characteristics are discussed. The results are in good agreement with the experimental data.
基金National R&D Program through the National Research Foundation of Korea(NRF)(grant nos.2022M3H4A1A01008918 and 2021M3H4A1A01002695)the Korea Research Institute of Chemical Technology Core Research Program funded by the Korea Research Council for Industrial Science and Technology(grant no.KS2222-10).
文摘Advances in energy conversion and storage technologies,such as water electrolyzers,rechargeable metal-air batteries,and fuel cells,have enabled a renewable and sustainable future.The efficiency and effectiveness of these technologies largely relies on the physicochemical properties of the functional materials used,specifically electrocatalysts.Pulsed laser deposition(PLD)is a powerful technique for the synthesis of thin film materials,offering a unique platform for understanding electrochemical reaction mechanisms and searching for low-cost and high-performance electrocatalysts.In this mini-review,we present the latest studies in which thin film materials(mainly focused on perovskite oxide thin films)via PLD have been actively utilized in the field of electrocatalysis.The fundamentals and advantages of PLD in the synthesis of thin films are discussed first.Then,emerging types of thin films associated with electrochemical applications are presented.Special emphasis is placed on material design methods to reveal the reaction mechanisms and establish the structure–performance relationships by understanding structural variations in precatalysts and surface reconstruction under reaction conditions.Finally,we discuss remaining challenges and future perspectives.
文摘Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings,owing to their combination of various properties that are essential for bio-implants,such as osteointegration and antibacterial character.In the present study,thin hopeite coatings were produced by Pulsed laser deposition(PLD)and radio frequency magnetron sputtering(RFMS)on Ti64 substrates.The obtained hopeite coatings were annealed at 500°C in ambient air and studied in terms of surface morphology,phase composition,surface roughness,adhesion strength,antibacterial efficacy,apatite forming ability,and surface wettability by scanning electron microscope(SEM),X-ray diffraction(XRD),atomic force microscope(AFM),tensometer,fluorescence-activated cell sorting(FACS),simulated body fluid(SBF)immersion test and contact angle goniometer,respectively.Furthermore,based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates,provides effective alternatives to conventional coatings,largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.
基金supported by the National Natural Science Foundation of China (No.10974077)the Project of Shandong Province Higher Educational Science and Technology Program (No.J08LI04)
文摘ZnO/diamond-like carbon (DLC) thin films are deposited by pulsed laser deposition (PLD) on Si (111) wafer. Visible room-temperature photoluminescence (PL) is observed from ZnO/DLC thin films by fluorescence spectrophotometer. The Gaussian curve fitting of PL spectra reveals that the broadband visible emission contains three components with λ=508 nm, 554 nm and 698 nm. The origin and possible mechanism of the visible PL are discussed, and they can be attributed to the PL recombination of ZnO and DLC thin films.
基金supported by the National Natural Science Foundation of China(No.11144010)the Innovation Project of Ludong University(No.LY20062802)
文摘ZnO/diamond-like carbon(DLC)thin films are deposited by pulsed laser deposition(PLD),and the room-temperature photoluminescence(PL)is investigated.Using a fluorescence spectrophotometer,we obtain the PL spectra of DLC/Si and ZnO/Si thin films deposited at different substrate temperatures.The ZnO/DLC thin films show a broadband emission almost containing the entire visible spectrum.The Gaussian fitting curves of PL spectra reveal that the visible emission of ZnO/DLC thin films consists of three peaks centered at 381 nm,526 nm and 682 nm,which are attributed to the radiative recombination of ZnO and DLC,respectively.The Commission International de l,Eclairage(CIE)1931(x,y)chromaticity space of ZnO/DLC thin films indicates that the visible PL spectrum is very close to the standard white-light region.
基金Project(2012-0001900)supported by the National Research Foundation of Korea
文摘Cu bump was transferred using a focused laser pulse for microelectronic packaging.An Nd:YAG laser pulse (maximum energy of 500 mJ;wavelength of 1064 nm;fluences of 0.4-2.1 kJ/cm2) was irradiated on a sacrificial absorption layer with copper coating.The focused laser beam induced plasma between the semi-transparent donor slide and the sacrificial layer,causing a shock wave.The shock wave pressure pushed the Cu layer and transferred material to deposit a bump on substrate.A beam-shaper was used to produce uniform pressure at the interface to reduce fragmentation of the transferred material on the substrate.The calculated shock wave pressure with respect to laser fluence was 1-3 GPa.A Cu bump of diameter of 200 μm was successfully deposited at laser fluence of 0.6 kJ/cm 2.The pressure control at the sacrificial layer using a laser pulse was critical to produce a bump with less fragmentation.The technique can be applied to forming Cu bump for an interconnecting process in electronics.
基金partially supported by the US Department of Energy
文摘A high-throughput multi-plume pulsed-laser deposition （MPPLD） system has been demonstrated and compared to previous techniques. Whereas most combinatorial pulsedlaser deposition （PLD） systems have focused on achieving thickness uniformity using sequential multilayer deposition and masking followed by post-deposition annealing, MPPLD directly deposits a compositionally varied library of compounds using the directionality of PLD plumes and the resulting spatial variations of deposition rate. This system is more suitable for high-throughput compound thin-film fabrication.
文摘TiO2 thin films were prepared on glass substrates using the PLD (Pulsed Laser Deposition) technique. In order to carry out the ablation process, a Nd:YAG laser was used emitting in 1064 nm wavelength at 10 Hz repetition rate, set up for operating in both single-pulse and multi-pulse regimes. A comparison of the deposition rate, the optical and morphological properties of the layers obtained from both ablation regimes was made, which showed that the multi-pulsed ablation produced layers with a higher surface quality and better optical properties.
基金the National Natural Science Foundation of China(61674165,61604167,61574160,61704183,61404159,11604366)the Natural Science Foundation of Jiangsu Province(BK20170432,BK20160397,BK20140394)+2 种基金the National Key R&D Program of China(2016YFB0401803)the Strategic Priority Research Program of the Chinese Academy of Science(XDA09020401)XRD,AFM and TEM experiments were performed at the Platform for Characterization&Test,Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO),Chinese Academy of Sciences.
文摘In this work,we have successfully grown high quality epitaxialβ-Ga_(2)O_(3)thin films onβ-Ga_(2)O_(3)(100)and Al_(2)O_(3)(0001)substrates using pulsed laser deposition(PLD).By optimizing temperature and oxygen pressure,the best conditions were found to be 650-700℃and 0.5 Pa.To further improve the quality of hetero-epitaxialβ-Ga_(2)O_(3),the sapphire substrates were pretreated for atomic terraced surface by chemical cleaning and high temperature annealing.From the optical transmittance measurements,the films grown at 600-750℃exhibit a clear absorption edge at deep ultraviolet region around 250-275 nm wavelength.High resolution transmission electron microscope(HRTEM)images and X-ray diffraction(XRD)patterns demonstrate thatβ-Ga_(2)O_(3)(-201)//Al_(2)O_(3)(0001)epitaxial texture dominated the epitaxial oxide films on sapphire substrate,which opens up the possibilities of high power electric devices.
