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
An experimental study of bioheat transfer characteristics induced bypulsed-laser irradiation was presented. The heat transfer characteristics of bio-materials, and theinfluences of pulse duration, power density, speci...An experimental study of bioheat transfer characteristics induced bypulsed-laser irradiation was presented. The heat transfer characteristics of bio-materials, and theinfluences of pulse duration, power density, species of bio-materials, thickness and initialmoisture content of bio-materials on heat transfer were studied in details. The experimental resultsindicate that the penetration and absorption of laser in bio-materials are considerable, the heattransfer inside the bio-materials should include the effects of volumetric absorption, pulseduration, power density, bio-materials thickness, and material species have a significant influenceon the temperature variation.展开更多
Wearable photodetectors have come under the limelight of optoelectronic technologies on account of multiple advantages spanning light weight,easy-portability,excellent bendability,outstanding conformability,etc.Among ...Wearable photodetectors have come under the limelight of optoelectronic technologies on account of multiple advantages spanning light weight,easy-portability,excellent bendability,outstanding conformability,etc.Among diverse candidate materials,low-dimensional van der Waals materials(LDvdWMs)have emerged to be preeminent owing to the dangling-bond-free surface,exceptional carrier mobility,nanoscale dimensionality,and excellent light-harvesting capability.However,to date,the majority of flexible LDvdWM photodetectors have been fabricated through exfoliation-,transfer-,or solution-processing methods,which are plagued by limitations such as low production yield,inadequate photosensitivity,and sluggish response rate.Thus far,constructing LDvdWM photodetectors in situ on flexible substrates remains quite challenging due to the irreconcilable contradiction between the weak robustness of flexible polymer substrates against high temperature and the large thermal budget required for crystallization.This study develops scalable preparation of Sb_(2)Se_(3)nanofilm directly on flexible polyimide substrates by exploiting pulsed-laser deposition(PLD),where highly energetic species can be generated to enable overcoming the reaction barrier for crystallization at a relatively low temperature.The corresponding Sb_(2)Se_(3)photodetectors have exhibited high responsivity of 1.15 A/W,exceptional external quantum efficiency of 269%,and impressive specific detectivity reaching 2.4×10^(11)Jones,coupled with swift switching characteristics.Importantly,excellent durability to repeated bending treatments has been confirmed by the consistent photoresponse over 500 convex/concave bending cycles.Furthermore,the device has showcased strong robustness against extrinsic impinging.In the end,by using Sb_(2)Se_(3)photodetectors as sensing components,wide-band imaging beyond human vision and heart rate monitoring have been realized.This study has underscored the high efficacy of PLD for reconciling the long-standing contradiction between the weak robustness of flexible polymer substrates against high temperature and the substantial thermal energy required for crystallization,opening new opportunities towards next-generation wearable optoelectronic industry.展开更多
TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. Th...TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2/p-Si interface are 1.8×10 12 cm -2 and 2×10 12 eV -1·cm -2, respectively. The conduction mechanisms of as-deposited films are also discussed.展开更多
Pulsed-laser deposition has been developed to prepare large-area In_(2)S_(3)nanofilms and their photoelectric characteristics have been investigated.The In_(2)S_(3)nanofilm grown under 500℃is highly oriented along th...Pulsed-laser deposition has been developed to prepare large-area In_(2)S_(3)nanofilms and their photoelectric characteristics have been investigated.The In_(2)S_(3)nanofilm grown under 500℃is highly oriented along the(103)direction with exceptional crystallinity.The corresponding(103)-oriented In_(2)S_(3)photodetectors exhibit broadband photoresponse from 370.6 nm to 1064 nm.Under 635 nm illumination,the optimized responsivity,external quantum efficiency,and detectivity reach 19.8 A/W,3869%,and 2.59×10^(12)Jones,respectively.In addition,the device exhibits short rise/decay time of 3.9/3.0 ms.Of note,first-principles calculations have unveiled that the effective carrier mass along the(103)lattice plane is much smaller than those along the(100),(110)and(111)lattice planes,which thereby enables high-efficiency transport of photocarriers and thereby the excellent photosensitivity.Profited from the sizable bandgap,the In_(2)S_(3)photodetectors also showcase strong robustness against elevated operating temperature.In the end,proof-of-concept imaging application beyond human vision and under high operating temperature as well as heart rate monitoring have been achieved by using the In_(2)S_(3)device of the sensing component.This study introduces a novel crystal orientation engineering paradigm for the implementation of next-generation advanced optoelectronic systems.展开更多
In this work,the microstructure and tensile properties of DD32 single-crystal(SC)superalloy repaired by laser metal forming(LMF)using pulsed laser have been studied in detail.The microstructures of the deposited sampl...In this work,the microstructure and tensile properties of DD32 single-crystal(SC)superalloy repaired by laser metal forming(LMF)using pulsed laser have been studied in detail.The microstructures of the deposited samples and the tensile-ruptured samples were characterized by optical microscopy(OM),transmission electron microscope(TEM)and scanning electron microscope(SEM).Due to high cooling rate,the primary dendrite spacing in the deposited area(17.2μm)was apparently smaller than that in the substrate area(307μm),and the carbides in the deposited samples were also smaller compared with that in the substrate area.The formation of(γ+γ’)eutectic in the initial layer of repaired SC was inhibited because of the high cooling rate.As the deposition proceeded,the cooling rate decreased,and the(γ+γ’)eutectic increased gradually.The(γ+γ’)eutectic at heat-affected zone(HAZ)in the molten pool dissolved partly because of the high temperature at HAZ,but there were still residual eutectics.Tensile test results showed that tensile behavior of repaired SC at different temperatures was closely related to the MC carbides,solidification porosity,γ’phase,and(γ+γ’)eutectic.At moderate temperature,the samples tested fractured preferentially at the substrate area due to the fragmentation of the coarse MC carbide in the substrate area.At elevated temperature,the(γ+γ’)eutectic and solidification porosity in the deposited area became the source of cracks,which deteriorated the high-temperature properties and made the samples rupture at the deposited area preferentially.展开更多
Epitaxial ZnO films are grown on Al2O3 （0001） by the MOCVD method. These films are high quality wurtzite crystals with （0001） orientation. Big hexagonal crystallites （diameter from several decades to 100 μm） ar...Epitaxial ZnO films are grown on Al2O3 （0001） by the MOCVD method. These films are high quality wurtzite crystals with （0001） orientation. Big hexagonal crystallites （diameter from several decades to 100 μm） are found on the surface. Inside these crystallites, a stronger luminescence is observed compared with the plain area. Transmission electronic microscopy reveals that the film is thicker inside the hexagonal crystallites than the plain area, and some crystallites are not connected with each other and are slightly rotated with respect to their neighbours.展开更多
Nano-diamond like carbon（DLC） thin films were prepared on fused silica and Cu substrates by the pulsed-laser deposition technique with different laser intensities. Step-measurement, atomic force microscope（AFM）, U...Nano-diamond like carbon（DLC） thin films were prepared on fused silica and Cu substrates by the pulsed-laser deposition technique with different laser intensities. Step-measurement, atomic force microscope（AFM）, UV-VIS-NIR transmittance spectroscopy and Raman spectroscopy were used to characterize the films. It was shown that the deposition rate increases with the laser intensity, and the films prepared under different laser intensities show different transparency. Raman measurement showed that the content of sp^3 of the Nano-DLC thin films decreases with the laser intensity. The field emission properties of the Nano-DLC thin films on Cu substrates were studied by the conventional diode method, which showed that the turn-on field increases and the current density decreases with sp^3 content in the films. A lower turn-on field of 6 V/um and a higher current density of 1 uA/cm^2 were obtained for Nano-DLC thin films on Cu substrate.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
Perovskite-structured barium strontium titanate[Ba_(1-x)Sr_(x)Ti O_(3),x=0.1–0.9] films have been epitaxially fabricated by using a pulsed-laser deposition technique.The third-order nonlinear optical properties were ...Perovskite-structured barium strontium titanate[Ba_(1-x)Sr_(x)Ti O_(3),x=0.1–0.9] films have been epitaxially fabricated by using a pulsed-laser deposition technique.The third-order nonlinear optical properties were studied through a z-scan method,allowing the resolution of the nonlinear refractive and absorptive contributions to the responses.Although all the samples show almost the same value of nonlinear absorption coefficient,the extracted nonlinear refractive index of the sample of x=0.3 is apparently larger than that of other samples.Dependency of the nonlinear optical properties on the Ba/Sr ratio is discussed in terms of the crystal phase transformation and metal-oxygen bond length of the selected materials.展开更多
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.
基金This research was financially supported by the Chinese National Key Foundation Research Subject (No.G2000026305), National Natural Science Foundation of China (No.50276060), and the director foundation of Institute of Engineering Thermophysics, Chinese A
文摘An experimental study of bioheat transfer characteristics induced bypulsed-laser irradiation was presented. The heat transfer characteristics of bio-materials, and theinfluences of pulse duration, power density, species of bio-materials, thickness and initialmoisture content of bio-materials on heat transfer were studied in details. The experimental resultsindicate that the penetration and absorption of laser in bio-materials are considerable, the heattransfer inside the bio-materials should include the effects of volumetric absorption, pulseduration, power density, bio-materials thickness, and material species have a significant influenceon the temperature variation.
基金financially supported by National Natural Science Foundation of China(Nos.U2001215,52272175,12104517)Natural Science Foundation of Guangdong Province(Nos.2022A1515011487,2021A1515110403)+1 种基金Young Top Talents Program(No.2021QN02C068)State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-sen University).
文摘Wearable photodetectors have come under the limelight of optoelectronic technologies on account of multiple advantages spanning light weight,easy-portability,excellent bendability,outstanding conformability,etc.Among diverse candidate materials,low-dimensional van der Waals materials(LDvdWMs)have emerged to be preeminent owing to the dangling-bond-free surface,exceptional carrier mobility,nanoscale dimensionality,and excellent light-harvesting capability.However,to date,the majority of flexible LDvdWM photodetectors have been fabricated through exfoliation-,transfer-,or solution-processing methods,which are plagued by limitations such as low production yield,inadequate photosensitivity,and sluggish response rate.Thus far,constructing LDvdWM photodetectors in situ on flexible substrates remains quite challenging due to the irreconcilable contradiction between the weak robustness of flexible polymer substrates against high temperature and the large thermal budget required for crystallization.This study develops scalable preparation of Sb_(2)Se_(3)nanofilm directly on flexible polyimide substrates by exploiting pulsed-laser deposition(PLD),where highly energetic species can be generated to enable overcoming the reaction barrier for crystallization at a relatively low temperature.The corresponding Sb_(2)Se_(3)photodetectors have exhibited high responsivity of 1.15 A/W,exceptional external quantum efficiency of 269%,and impressive specific detectivity reaching 2.4×10^(11)Jones,coupled with swift switching characteristics.Importantly,excellent durability to repeated bending treatments has been confirmed by the consistent photoresponse over 500 convex/concave bending cycles.Furthermore,the device has showcased strong robustness against extrinsic impinging.In the end,by using Sb_(2)Se_(3)photodetectors as sensing components,wide-band imaging beyond human vision and heart rate monitoring have been realized.This study has underscored the high efficacy of PLD for reconciling the long-standing contradiction between the weak robustness of flexible polymer substrates against high temperature and the substantial thermal energy required for crystallization,opening new opportunities towards next-generation wearable optoelectronic industry.
文摘TiO-2 thin films have bee deposited on p-Si(111) substrates by pulsed-laser ablation of metallic Ti target in the O-3 ambient. The current-voltage and capacitance-voltage of the Al/TiO-2/Si capacitors are measured. The results show that the dielectric constant of thin film after being annealed at 700℃ is found to be 46, and the border trap density and the interface state density at the TiO-2/p-Si interface are 1.8×10 12 cm -2 and 2×10 12 eV -1·cm -2, respectively. The conduction mechanisms of as-deposited films are also discussed.
基金supported by the National Natural Science Foundation of China(Nos.52272175,U2001215 and 12474226)the Guangzhou Science and Technology Programme(No.2025A04J2596)+2 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515012688,2022A1515011487,2021A1515110403 and 2023A1515010652)the Young Top Talents Program(No.2021QN02C068)State Key Laboratory of Optoelectronic Materials and Technologies of Sun Yat-sen University.
文摘Pulsed-laser deposition has been developed to prepare large-area In_(2)S_(3)nanofilms and their photoelectric characteristics have been investigated.The In_(2)S_(3)nanofilm grown under 500℃is highly oriented along the(103)direction with exceptional crystallinity.The corresponding(103)-oriented In_(2)S_(3)photodetectors exhibit broadband photoresponse from 370.6 nm to 1064 nm.Under 635 nm illumination,the optimized responsivity,external quantum efficiency,and detectivity reach 19.8 A/W,3869%,and 2.59×10^(12)Jones,respectively.In addition,the device exhibits short rise/decay time of 3.9/3.0 ms.Of note,first-principles calculations have unveiled that the effective carrier mass along the(103)lattice plane is much smaller than those along the(100),(110)and(111)lattice planes,which thereby enables high-efficiency transport of photocarriers and thereby the excellent photosensitivity.Profited from the sizable bandgap,the In_(2)S_(3)photodetectors also showcase strong robustness against elevated operating temperature.In the end,proof-of-concept imaging application beyond human vision and under high operating temperature as well as heart rate monitoring have been achieved by using the In_(2)S_(3)device of the sensing component.This study introduces a novel crystal orientation engineering paradigm for the implementation of next-generation advanced optoelectronic systems.
基金the National Key R&D Program of China(No.2018YFB1106600),the National Key R&D Program of China(Nos.2017YFA0700703 and 2018YFB1106000)the National Natural Science Foundation of China(NSFC)(Nos.51771190,51671189,U1508213)+1 种基金the National High Technology Research and Development Program(“863”)(No.2014AA041701)the Fund of the State Key Laboratory of Solidification Processing in NWPU(No.SKLSP201834)。
文摘In this work,the microstructure and tensile properties of DD32 single-crystal(SC)superalloy repaired by laser metal forming(LMF)using pulsed laser have been studied in detail.The microstructures of the deposited samples and the tensile-ruptured samples were characterized by optical microscopy(OM),transmission electron microscope(TEM)and scanning electron microscope(SEM).Due to high cooling rate,the primary dendrite spacing in the deposited area(17.2μm)was apparently smaller than that in the substrate area(307μm),and the carbides in the deposited samples were also smaller compared with that in the substrate area.The formation of(γ+γ’)eutectic in the initial layer of repaired SC was inhibited because of the high cooling rate.As the deposition proceeded,the cooling rate decreased,and the(γ+γ’)eutectic increased gradually.The(γ+γ’)eutectic at heat-affected zone(HAZ)in the molten pool dissolved partly because of the high temperature at HAZ,but there were still residual eutectics.Tensile test results showed that tensile behavior of repaired SC at different temperatures was closely related to the MC carbides,solidification porosity,γ’phase,and(γ+γ’)eutectic.At moderate temperature,the samples tested fractured preferentially at the substrate area due to the fragmentation of the coarse MC carbide in the substrate area.At elevated temperature,the(γ+γ’)eutectic and solidification porosity in the deposited area became the source of cracks,which deteriorated the high-temperature properties and made the samples rupture at the deposited area preferentially.
基金Supported by the National Natural Science Foundation of China under Grant No 10375004, and the Key Laboratory of Heavy Ion Physics, Ministry of Education of China.
文摘Epitaxial ZnO films are grown on Al2O3 （0001） by the MOCVD method. These films are high quality wurtzite crystals with （0001） orientation. Big hexagonal crystallites （diameter from several decades to 100 μm） are found on the surface. Inside these crystallites, a stronger luminescence is observed compared with the plain area. Transmission electronic microscopy reveals that the film is thicker inside the hexagonal crystallites than the plain area, and some crystallites are not connected with each other and are slightly rotated with respect to their neighbours.
文摘Nano-diamond like carbon（DLC） thin films were prepared on fused silica and Cu substrates by the pulsed-laser deposition technique with different laser intensities. Step-measurement, atomic force microscope（AFM）, UV-VIS-NIR transmittance spectroscopy and Raman spectroscopy were used to characterize the films. It was shown that the deposition rate increases with the laser intensity, and the films prepared under different laser intensities show different transparency. Raman measurement showed that the content of sp^3 of the Nano-DLC thin films decreases with the laser intensity. The field emission properties of the Nano-DLC thin films on Cu substrates were studied by the conventional diode method, which showed that the turn-on field increases and the current density decreases with sp^3 content in the films. A lower turn-on field of 6 V/um and a higher current density of 1 uA/cm^2 were obtained for Nano-DLC thin films on Cu substrate.
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supported by the National Natural Science Foundation of China(No.10704065)the Graduate Innovation Foundation of Yantai University(No.KGIFYTU2212)。
文摘Perovskite-structured barium strontium titanate[Ba_(1-x)Sr_(x)Ti O_(3),x=0.1–0.9] films have been epitaxially fabricated by using a pulsed-laser deposition technique.The third-order nonlinear optical properties were studied through a z-scan method,allowing the resolution of the nonlinear refractive and absorptive contributions to the responses.Although all the samples show almost the same value of nonlinear absorption coefficient,the extracted nonlinear refractive index of the sample of x=0.3 is apparently larger than that of other samples.Dependency of the nonlinear optical properties on the Ba/Sr ratio is discussed in terms of the crystal phase transformation and metal-oxygen bond length of the selected materials.
