The new component of melilite type crystal CaNdAl_(3)O_(7)(CNA)was grown by the Czochralski pulling method.Single crystal structure analysis was conducted.It is found that the CNA crystal belongs to the tetragonal sys...The new component of melilite type crystal CaNdAl_(3)O_(7)(CNA)was grown by the Czochralski pulling method.Single crystal structure analysis was conducted.It is found that the CNA crystal belongs to the tetragonal system with P-421m space group.The cell parameters a=b=0.77461 nm and c=0.51089 nm.The density and Mohs hardness of CNA crystal are 4.08 g/cm^(3) and 5.45,respectively.The specific heat of the crystal is 0.57-0.77 J/(g·K)in the temperature range of 30-300℃.X-ray photoelectron spectro scopy(XPS)shows that the crystal has stable atomic valence states and chemical environment.The vibration state of polyhedra groups in the crystal was measured by Raman spectra,and the piezoelectric response was analyzed based on the calculated results for the polyhedra polarization dipole moments.The relative dielectric permittivity of the CNA crystal at room temperature was determined to be 11.80 and the electrical resistivity was measured to be on the order of 5×10^(6)Ω·cm at 800℃.展开更多
Silicon carbide offers distinct advantages in the field of power electronic devices.However,manufacturing processes remain a significant barrier to its widespread adoption.Polycrystalline SiC is less expensive and eas...Silicon carbide offers distinct advantages in the field of power electronic devices.However,manufacturing processes remain a significant barrier to its widespread adoption.Polycrystalline SiC is less expensive and easier to produce than single crystal.But stabilizing and controlling its performance are critical challenges that must be addressed urgently.Due to its material properties and excellent performance in applications,3C-SiC is gaining increasing attention in research.This article presents the electrical and material properties of a series of polycrystalline 3C-SiC samples and investigates their interrelationship.The samples were examined using TEM,which confirmed their polycrystalline structure.Combined with XRD and Raman spectroscopy,the grain orientations within the samples were analyzed,and the presence of stress was verified.EBSD was employed to statistically examine the grain structure and size across samples.For samples with similar doping levels,grain size is the most influential factor in determining electrical characteristics.Further EBSD measurements reveal the relationship between resistivity and grain size as log(ρ)=-1.93+8.67/d.These findings provide a foundation for the quantitative control and application of polycrystalline 3C-SiC.This work offers theoretical evidence for optimizing the performance tuning of 3C-SiC ceramics and enhancing their effectiveness in electronic applications.展开更多
The investigation of thermal transport properties of materials has become increasingly important in technological applications,including thermal management and energy conversion.Recently,ultrahigh or low thermal condu...The investigation of thermal transport properties of materials has become increasingly important in technological applications,including thermal management and energy conversion.Recently,ultrahigh or low thermal conductivity has been reported in nitride,boride,and chalcogenide by different strategies.However,the strategy to design oxide crystals with unique thermal properties is also a challenge.In this work,a new ternary oxide crystal Ga_(2)TeO_(6) is designed and expected to show high thermal conductivity due to its lone pairs-free octahedra connected along the caxis by sharing edges.The thermal conductivities of Ga_(2)TeO_(6) crystal are determined to be 19.2 and 23.9Wm^(-1) K^(-1) along the a-and c-axis directions at 323 K,respectively,which are significantly higher than those of most reported oxide crystals.First-principles calculations and crystal structure analyses reveal that the Ga_(2)TeO_(6) crystal shows high sound velocity and weak lattice anharmonicity due to lone pairs-free octahedra and highly symmetric group arrangement.The results suggest that much attention must be paid to the polyhedron with lone pairs and its arrangement in materials design to balance the functions and thermal properties.展开更多
The transition of cobalt ions located at tetrahedral sites will produce strong absorption in the visible and nearinfrared regions,and is expected to work in a passively Q-switched solid-state laser at the eye-safe wav...The transition of cobalt ions located at tetrahedral sites will produce strong absorption in the visible and nearinfrared regions,and is expected to work in a passively Q-switched solid-state laser at the eye-safe wavelength of 1.5μm.In this study,Co^(2+)ions were introduced into the wide bandgap semiconductor material ZnGa_(2)O_(4),and large-sized and high-quality Co^(2+)-doped ZnGa_(2)O_(4)crystals with a volume of about 20 cm^(3)were grown using the vertical gradient freeze(VGF)method.Crystal structure and optical properties were analyzed using X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and absorption spectroscopy.XRD results show that the Co^(2+)-doped ZnGa_(2)O_(4)crystal has a pure spinel phase without impurity phases and the rocking curve full width at half maximum(FWHM)is only 58 arcsec.The concentration of Co^(2+)in Co^(2+)-doped ZnGa_(2)O_(4)crystals was determined to be 0.2 at.%by the energy dispersive X-ray spectroscopy.The optical band gap of Co^(2+)-doped ZnGa_(2)O_(4)crystals is 4.44 eV.The optical absorption spectrum for Co^(2+)-doped ZnGa_(2)O_(4)reveals a prominent visible absorption band within 550−670 nm and a wide absorption band spanning from 1100 to 1700 nm.This suggests that the Co^(2+)ions have substituted the Zn^(2+)ions,which are typically tetrahedrally coordinated,within the lattice structure of ZnGa_(2)O_(4).The visible region's absorption peak and the near-infrared broad absorption band are ascribed to the^(4)A_(2)(4F)→^(4)T_(1)(4P)and 4A2(4F)→^(4)T_(1)(4F)transitions,respectively.The optimal ground state absorption cross section was determined to be 3.07×10^(−19)cm^(2)in ZnGa_(2)O_(4),a value that is comparatively large within the context of similar materials.This finding suggests that ZnGa_(2)O_(4)is a promising candidate for use in near-infrared passive Q-switched solid-state lasers.展开更多
Professor Kazunari Domen at the Shinshu University and the University of Tokyo has pioneered materials and techniques for solar-driven water splitting using photocatalysts,a promising technology for contributing to th...Professor Kazunari Domen at the Shinshu University and the University of Tokyo has pioneered materials and techniques for solar-driven water splitting using photocatalysts,a promising technology for contributing to the construction of a sustainable and carbon-neutral society.In this paper,we summarize his groundbreaking contributions to photocatalytic water splitting and,more broadly,photocatalytic research.We highlight various novel functional photocatalytic materials,including oxides,(oxy)nitrides,and oxysulfides,along with innovative techniques such as cocatalyst engineering and Z-scheme system construction developed by the Domen Group.His team has also pioneered readily accessible and cost-effective photo(electro)chemical device fabrication methods,such as the particle-transfer method and thin-film-transfer method.Furthermore,their research has made significant contributions to understanding the(photo)catalytic mechanisms using advanced characterization techniques.Together with his research team,Professor Domen has set many milestones in the field of photocatalytic overall water splitting,notably demonstrating the first scalable and stable 100 m^(2)solar H_(2)production system using only water and sunlight.His work has revealed the potential for practical solar H2 production from water and sunlight,and highlighted the application of fundamental principles,combined with chemical and materials science tools,to design effective photocatalytic systems.Through this review,we focus on his research and the foundational design principles that can inspire the development of efficient photocatalytic systems for water splitting and solar fuel production.By building on his contributions,we anticipate a significant impact on addressing major global energy challenges.展开更多
Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to cr...Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies.The interaction between the laser,the implanted gold nanoparticles,and the crystal lattice induces permanent,localized modifications on the crystal surface.By fine-tuning the laser direct writing parameters,we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface,resulting in the display of red,green,blue,and pale-yellow colors.We investigated the influence of the implanted Au nanoparticles-particularly their localized surface plasmon resonances-on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy.Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser,thereby facilitating the generation of surface colors.This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.展开更多
Choice of crucible material is a key issue during the growth of AIN crystal. The stabilities at high temperature and life-spans of boron nitride （BN） crucible, tantalum （Ta） crucible and tungsten （W） crucible we...Choice of crucible material is a key issue during the growth of AIN crystal. The stabilities at high temperature and life-spans of boron nitride （BN） crucible, tantalum （Ta） crucible and tungsten （W） crucible were compared. Tantalum crucible behaved worse at high temperature and life-span was shortened as compared with the other two crucible materials. It was very crisp and easy to crack. In contrast, self-seeded AIN crystals with different morphologies could be obtained at different high temperatures using BN crucible. The boron nitride crucible was stable below 2200 ℃, above which it would decompose. Thus it was unsuitable for the bulky AIN crystal growth. Tungsten crucible could endure the temperatures higher than 2200℃. Unfortunately we could only get AIN polycrystallines using tungsten crucible. After 50- 100 hours＇ run, the crucible was destroyed completely due to the multiple deep cracks. XRD results of destroyed tungsten crucible indicated that the main phases are tungsten carbide and tungsten nitride.展开更多
The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,fle...The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.展开更多
High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for...High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC. Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.展开更多
As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislo...As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There's no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the(102) plane, the(101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of "shoulder part" during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.展开更多
Stimulated Raman scattering （SRS） of picosecond pulses is investigated in a new crystal SrWO4. The second harmonic generation of a mode-locked Nd：YAG laser system is used as the pump source. In an external singlepa...Stimulated Raman scattering （SRS） of picosecond pulses is investigated in a new crystal SrWO4. The second harmonic generation of a mode-locked Nd：YAG laser system is used as the pump source. In an external singlepass configuration, the SRS thresholds for the first to the fourth Stokes lines are measured. For the first Stokes line, the steady-state gain coefficient of the SrWO4 crystal is calculated to be 15.96cm//GW. In our experiment, as many as five Stokes lines （559.23 nm, 589.61 nm, 623.49 nm, 661.50 nm, 704.44 nm） and three anti-Stokes lines （506.97nm, 484.34 nm, 463.65nm） are observed, and the total conversion efficiency is as high as 62%.展开更多
Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established base...Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.展开更多
Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
One novel cobalt coordination polymer, {[Co（HTCB）（4,4＇btb）]＇HzO}n （1, H3TCB = 1,3,5-tris（4-carboxyphenyl）benzene, 4,4＇-btb = 4,4＇-bis（1,2,4-triazol-3-yl）biphenyl）, has been synthesized and characterized ...One novel cobalt coordination polymer, {[Co（HTCB）（4,4＇btb）]＇HzO}n （1, H3TCB = 1,3,5-tris（4-carboxyphenyl）benzene, 4,4＇-btb = 4,4＇-bis（1,2,4-triazol-3-yl）biphenyl）, has been synthesized and characterized by elemental analysis, IR, powder X-ray diffraction （PXRD）, and thermogravimetric （TG） analyses. X-ray diffraction analysis reveals that complex 1 is a 2D 2-fold interpenetrated {44,62}-sql [Co（HTCB）（4,4＇-btb）] sheet based on the 1D [Co（HTCB）]n chains and 1D [Co（4,4＇-btb）]n chains. The crystal of 1 crystallizes in triclinic, space group P1 with a = 9.529（12）, b = 13.914（16）, c = 14.906（17） A, V= 1903（4） A3, Z = 2, C45H34N6CoO71 Mr= 829.71, Dc = 1.448 g/cm3, F（000） = 858 andμ（MoKa） = 0.514 mm-1. The final R = 0.0655 and wR = 0.1136 for 6603 observed reflections with 1 〉 2a（/） and R = 0.1136 and wR = 0.1747 for all data.展开更多
During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different ...During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different concentration of Fe^3＋ dopant by traditional temperaturereduction method and ＂point-seed＂ rapid growth method. Furthermore, we examined the light scatter and measured the transmission of these KDP crystals. It is found that the dopant of Fe^3＋ ion can improve the stability of the KDP growth solution when its concentration is less than 30 ppm. The effects of Fe^3＋ ion on the growth habit and optical properties of KDP crystal are also obvious.展开更多
The growth of high-quality and large-size cerium-doped lutetium yttrium orthosilicate(Ce:(LuY)2 SiO5,Ce:LYSO)crystals with lower cost has great influence on their applications in various physical devices.According to ...The growth of high-quality and large-size cerium-doped lutetium yttrium orthosilicate(Ce:(LuY)2 SiO5,Ce:LYSO)crystals with lower cost has great influence on their applications in various physical devices.According to the chemical bonding theory of single crystal growth,the fast thermodynamic growth direction of Ce:LYSO is[010]direction.In this work,the maximum pulling rate of 3.5 mm/h is obtained along[010]direction of Ce:LYSO via the Czochralski(Cz)method.Finally,Ce:LYSO bulk single crystals with diameter of 64 mm and length of 220 mm and mass of 4.2 kg are grown.The luminescence performance of low-doped Ce:LYSO for nuclear irradiation(^(22)Na)detector device was studied.Light yield of26193 ph/MeV and decay time of 38 ns are obtained.The present work provides a promising fast growth approach to achieving large size functional bulk crystal via both thermodynamic and kinetic controls.展开更多
Dy：Lu2O3 was grown by the float-zone （Fz） method. According to the absorption spectrum, the Judd-Ofelt （JO） parameters Ω2, Ω4, and Ω6 were calculated to be 4.86 × 10-20 cm2, 2.02 × 10-20 cm2, and 1.7...Dy：Lu2O3 was grown by the float-zone （Fz） method. According to the absorption spectrum, the Judd-Ofelt （JO） parameters Ω2, Ω4, and Ω6 were calculated to be 4.86 × 10-20 cm2, 2.02 × 10-20 cm2, and 1.76 ×10-20 cm2, respectively. The emission cross-section at 574 nm corresponding to the 4F9/2 →6H13/2 transition was calculated to be 0.53 ×10 20 cm2. The yellow （4F9/2 →6H13/2 transition） to blue （4F9/2 →6H15/2 transition） intensity ratio ranges up to 12.9. The fluorescence lifetime of the 4F9/2 energy level was measured to be 112.1 μs. These results reveal that Dy：Lu2O3 is a promising material for use in yellow lasers.展开更多
We present the characteristics of bulk damage induced by the third harmonic of Nd：YAG laser irradiation in KDP and DKDP crystals. Bulk damage occurs as a few or a series of pinpoints consisting of a core and the defo...We present the characteristics of bulk damage induced by the third harmonic of Nd：YAG laser irradiation in KDP and DKDP crystals. Bulk damage occurs as a few or a series of pinpoints consisting of a core and the deforming zone. The results of a 1-on-1 test reveal that the pinpoint size increases with incvreasing fluence, and the pinpoint density increases exponentially with increasing fluence. The results of an s-on-1 test indicate that the pinpoint density increases gradually with laser pulse number, but the size does not grow. These results are consistent with a model in which nanoabsorbers are assumed to exist in the crystal and the initiation of damage is determined by heating them to the critical temperature.展开更多
By testing the number increase and size growth of surface and bulk laser induced damage in KDP and DKDP crystals, we observe different growth characteristics of surface and bulk damage under multiple 355nm laser irrad...By testing the number increase and size growth of surface and bulk laser induced damage in KDP and DKDP crystals, we observe different growth characteristics of surface and bulk damage under multiple 355nm laser irradiations. The size of the surface damage grows exponentially, but that of the bulk damage does not grow. In contrast, the bulk damage number increases, but that of surface damage does not increase significantly. We attribute the differences to the different formation of the damage initiators and the different damage testing volumes.展开更多
Rare earth(RE)takes an irreplaceable role in various fields,especially the high-tech electronics industry,which is usually comparable to the vitamin of industry.In the development of electromagnetic wave(EMW)absorptio...Rare earth(RE)takes an irreplaceable role in various fields,especially the high-tech electronics industry,which is usually comparable to the vitamin of industry.In the development of electromagnetic wave(EMW)absorption materials,the participation of RE makes a significant contribution as well,and great progress has been made.Abundant researches have illuminated that the strategy of both doping RE elements and constructing RE oxide composites exhibited huge potential for the fabrication of high-efficiency EMW absorption materials.We believe a systematic summary will be highly desired for a comprehensive understanding and future development.In this review,we first summarized the research background,basic principles,and mechanisms of EMW absorption.Then,we classify the RE EMW absorption materials into RE-doped ferrites,RE-transition metal intermetallics,RE oxides,and other categories,view their current progress by typical studies,and expound their respective features,strengths,weaknesses,and absorption mechanisms.Finally,the current challenges and future outlook of RE EMW absorption materials are highlighted,in the hope of guidance for a sound future development.展开更多
基金Project supported by the National Natural Science Foundation of China(52372008)Shandong Provincial Natural Science Foundation(ZR2020KA003,ZR2023QE165)。
文摘The new component of melilite type crystal CaNdAl_(3)O_(7)(CNA)was grown by the Czochralski pulling method.Single crystal structure analysis was conducted.It is found that the CNA crystal belongs to the tetragonal system with P-421m space group.The cell parameters a=b=0.77461 nm and c=0.51089 nm.The density and Mohs hardness of CNA crystal are 4.08 g/cm^(3) and 5.45,respectively.The specific heat of the crystal is 0.57-0.77 J/(g·K)in the temperature range of 30-300℃.X-ray photoelectron spectro scopy(XPS)shows that the crystal has stable atomic valence states and chemical environment.The vibration state of polyhedra groups in the crystal was measured by Raman spectra,and the piezoelectric response was analyzed based on the calculated results for the polyhedra polarization dipole moments.The relative dielectric permittivity of the CNA crystal at room temperature was determined to be 11.80 and the electrical resistivity was measured to be on the order of 5×10^(6)Ω·cm at 800℃.
基金supported in part by the Major Science and Technology Innovation Project of Shandong Province under Grant 2022CXGC010103Taishan Scholars Program of Shandong Province under Grant tstp20231210。
文摘Silicon carbide offers distinct advantages in the field of power electronic devices.However,manufacturing processes remain a significant barrier to its widespread adoption.Polycrystalline SiC is less expensive and easier to produce than single crystal.But stabilizing and controlling its performance are critical challenges that must be addressed urgently.Due to its material properties and excellent performance in applications,3C-SiC is gaining increasing attention in research.This article presents the electrical and material properties of a series of polycrystalline 3C-SiC samples and investigates their interrelationship.The samples were examined using TEM,which confirmed their polycrystalline structure.Combined with XRD and Raman spectroscopy,the grain orientations within the samples were analyzed,and the presence of stress was verified.EBSD was employed to statistically examine the grain structure and size across samples.For samples with similar doping levels,grain size is the most influential factor in determining electrical characteristics.Further EBSD measurements reveal the relationship between resistivity and grain size as log(ρ)=-1.93+8.67/d.These findings provide a foundation for the quantitative control and application of polycrystalline 3C-SiC.This work offers theoretical evidence for optimizing the performance tuning of 3C-SiC ceramics and enhancing their effectiveness in electronic applications.
基金supported by the National Natural Science Foundation of China(No.62175129)the Taishan Scholar of Shandong Province(No.tsqn202306014)the Qilu Young Scholar of Shandong University.
文摘The investigation of thermal transport properties of materials has become increasingly important in technological applications,including thermal management and energy conversion.Recently,ultrahigh or low thermal conductivity has been reported in nitride,boride,and chalcogenide by different strategies.However,the strategy to design oxide crystals with unique thermal properties is also a challenge.In this work,a new ternary oxide crystal Ga_(2)TeO_(6) is designed and expected to show high thermal conductivity due to its lone pairs-free octahedra connected along the caxis by sharing edges.The thermal conductivities of Ga_(2)TeO_(6) crystal are determined to be 19.2 and 23.9Wm^(-1) K^(-1) along the a-and c-axis directions at 323 K,respectively,which are significantly higher than those of most reported oxide crystals.First-principles calculations and crystal structure analyses reveal that the Ga_(2)TeO_(6) crystal shows high sound velocity and weak lattice anharmonicity due to lone pairs-free octahedra and highly symmetric group arrangement.The results suggest that much attention must be paid to the polyhedron with lone pairs and its arrangement in materials design to balance the functions and thermal properties.
基金the support by the fund of the National Key Research and Development Program of China (Grant No. 2024YFA1208800)National Natural Science Foundation of China (NSFC) (Grant No. U23A20358)+2 种基金Natural Science Foundation of Shandong Province (Grant Nos. ZR2023ZD05 and 2022TSGC2120)the Shenzhen Fundamental Research Program (Grant No. GJHZ20220913142605011)Xiaomi Foundation/Xiaomi Young Talents Program
文摘The transition of cobalt ions located at tetrahedral sites will produce strong absorption in the visible and nearinfrared regions,and is expected to work in a passively Q-switched solid-state laser at the eye-safe wavelength of 1.5μm.In this study,Co^(2+)ions were introduced into the wide bandgap semiconductor material ZnGa_(2)O_(4),and large-sized and high-quality Co^(2+)-doped ZnGa_(2)O_(4)crystals with a volume of about 20 cm^(3)were grown using the vertical gradient freeze(VGF)method.Crystal structure and optical properties were analyzed using X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and absorption spectroscopy.XRD results show that the Co^(2+)-doped ZnGa_(2)O_(4)crystal has a pure spinel phase without impurity phases and the rocking curve full width at half maximum(FWHM)is only 58 arcsec.The concentration of Co^(2+)in Co^(2+)-doped ZnGa_(2)O_(4)crystals was determined to be 0.2 at.%by the energy dispersive X-ray spectroscopy.The optical band gap of Co^(2+)-doped ZnGa_(2)O_(4)crystals is 4.44 eV.The optical absorption spectrum for Co^(2+)-doped ZnGa_(2)O_(4)reveals a prominent visible absorption band within 550−670 nm and a wide absorption band spanning from 1100 to 1700 nm.This suggests that the Co^(2+)ions have substituted the Zn^(2+)ions,which are typically tetrahedrally coordinated,within the lattice structure of ZnGa_(2)O_(4).The visible region's absorption peak and the near-infrared broad absorption band are ascribed to the^(4)A_(2)(4F)→^(4)T_(1)(4P)and 4A2(4F)→^(4)T_(1)(4F)transitions,respectively.The optimal ground state absorption cross section was determined to be 3.07×10^(−19)cm^(2)in ZnGa_(2)O_(4),a value that is comparatively large within the context of similar materials.This finding suggests that ZnGa_(2)O_(4)is a promising candidate for use in near-infrared passive Q-switched solid-state lasers.
基金supported by the Artificial Photosynthesis Project of the New Energy and Industrial Technology Development Organization(NEDO),the JST Fusion Oriented Research for disruptive Science and Technology Program(JPMJFR213D)JSPS KAKENHI(JP24K17774)Domen for his guidance during their PhD studies at the University of Tokyo,as well as for his ongoing support,encouragement,and mentorship.
文摘Professor Kazunari Domen at the Shinshu University and the University of Tokyo has pioneered materials and techniques for solar-driven water splitting using photocatalysts,a promising technology for contributing to the construction of a sustainable and carbon-neutral society.In this paper,we summarize his groundbreaking contributions to photocatalytic water splitting and,more broadly,photocatalytic research.We highlight various novel functional photocatalytic materials,including oxides,(oxy)nitrides,and oxysulfides,along with innovative techniques such as cocatalyst engineering and Z-scheme system construction developed by the Domen Group.His team has also pioneered readily accessible and cost-effective photo(electro)chemical device fabrication methods,such as the particle-transfer method and thin-film-transfer method.Furthermore,their research has made significant contributions to understanding the(photo)catalytic mechanisms using advanced characterization techniques.Together with his research team,Professor Domen has set many milestones in the field of photocatalytic overall water splitting,notably demonstrating the first scalable and stable 100 m^(2)solar H_(2)production system using only water and sunlight.His work has revealed the potential for practical solar H2 production from water and sunlight,and highlighted the application of fundamental principles,combined with chemical and materials science tools,to design effective photocatalytic systems.Through this review,we focus on his research and the foundational design principles that can inspire the development of efficient photocatalytic systems for water splitting and solar fuel production.By building on his contributions,we anticipate a significant impact on addressing major global energy challenges.
基金supported by the National Natural Science Foundation of China (NSFC) (Grants No. 12274236, 12134009, 12074223)Shandong Provincial Natural Science Foundation (Grants No. 2022HWYQ-047, ZR2024MA041)+3 种基金Taishan Scholars Program of Shandong Province (Grants No. tsqn201909041)“Qilu Young Scholar Program” of Shandong UniversityCore Facility Sharing Platform of Shandong UniversityOpen Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems
文摘Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications.In this study,we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies.The interaction between the laser,the implanted gold nanoparticles,and the crystal lattice induces permanent,localized modifications on the crystal surface.By fine-tuning the laser direct writing parameters,we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface,resulting in the display of red,green,blue,and pale-yellow colors.We investigated the influence of the implanted Au nanoparticles-particularly their localized surface plasmon resonances-on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy.Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser,thereby facilitating the generation of surface colors.This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.
基金the National Natural Science Foundation of China (No. 50472068)the Program for New Century Excellent Talents in University
文摘Choice of crucible material is a key issue during the growth of AIN crystal. The stabilities at high temperature and life-spans of boron nitride （BN） crucible, tantalum （Ta） crucible and tungsten （W） crucible were compared. Tantalum crucible behaved worse at high temperature and life-span was shortened as compared with the other two crucible materials. It was very crisp and easy to crack. In contrast, self-seeded AIN crystals with different morphologies could be obtained at different high temperatures using BN crucible. The boron nitride crucible was stable below 2200 ℃, above which it would decompose. Thus it was unsuitable for the bulky AIN crystal growth. Tungsten crucible could endure the temperatures higher than 2200℃. Unfortunately we could only get AIN polycrystallines using tungsten crucible. After 50- 100 hours＇ run, the crucible was destroyed completely due to the multiple deep cracks. XRD results of destroyed tungsten crucible indicated that the main phases are tungsten carbide and tungsten nitride.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051)+5 种基金Open Research Fund of State Key Laboratory of Materials for Integrated Circuits(SKLJC-K2024-12)the Shanghai Sailing Program(23YF1402200,23YF1402400)Natural Science Foundation of Jiangsu Province(BK20240424)Taishan Scholar Foundation of Shandong Province(tsqn202408006)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University.
文摘The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.
文摘High purity silicon carbide （SIC） powder was synthesized in-situ by chemical reaction between silicon and carbon powder. In order to ensure that the impurity concentration of the resulting SiC powder is suitable for high-resistivity SiC single crystal growth, the preparation technology of SiC powder is different from that of SiC ceramic. The influence of the shape and size of carbon particles on the morphology and phase composition of the obtained SiC powder were discussed. The phase composition and morphology of the products were investigated by X-ray diffraction, Raman microspectroscopy and scanning electron microscopy. The results show that the composition of resulting SiC by in-situ synthesis from Si/C mixture strongly depends on the nature of the carbon source, which corresponds to the particle size and shape, as well as the preparation temperature. In the experimental conditions, flake graphite is more suitable for the synthesis of SiC powder than activated carbon because of its relatively smaller particle size and flake shape, which make the conversion more complete. The major phase composition of the full conversion products is β-SiC, with traces of α-SiC. Glow discharge mass spectroscopy measurements indicated that SiC powder synthesized with this chemical reaction method can meet the purity demand for the growth of high-resistivity SiC single crystals.
基金the Financial support from the National key Research and Development Program of China(Nso.2018YFB0406502,2016YFB1102201)the National Natural Science Foundation of China(Grant No.51321091)+2 种基金the key Research and Development Program of Shandong Province(No.2018CXGC0410)the Young Scholars Program of Shandong University(No.2015WLJH36)the 111 Project 2.0(No.BP2018013)
文摘As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There's no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the(102) plane, the(101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of "shoulder part" during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50590401 and 60508010.
文摘Stimulated Raman scattering （SRS） of picosecond pulses is investigated in a new crystal SrWO4. The second harmonic generation of a mode-locked Nd：YAG laser system is used as the pump source. In an external singlepass configuration, the SRS thresholds for the first to the fourth Stokes lines are measured. For the first Stokes line, the steady-state gain coefficient of the SrWO4 crystal is calculated to be 15.96cm//GW. In our experiment, as many as five Stokes lines （559.23 nm, 589.61 nm, 623.49 nm, 661.50 nm, 704.44 nm） and three anti-Stokes lines （506.97nm, 484.34 nm, 463.65nm） are observed, and the total conversion efficiency is as high as 62%.
基金financial support from National Natural Science Foundation of China(No.61775120).
文摘Optical waveguides are far more than mere connecting elements in integrated optical systems and circuits.Benefiting from their high optical confinement and miniaturized footprints,waveguide structures established based on crystalline materials,particularly,are opening exciting possibilities and opportunities in photonic chips by facilitating their on-chip integration with different functionalities and highly compact photonic circuits.Femtosecond-laser-direct writing(FsLDW),as a true three-dimensional(3D)micromachining and microfabrication technology,allows rapid prototyping of on-demand waveguide geometries inside transparent materials via localized material modification.The success of FsLDW lies not only in its unsurpassed aptitude for realizing 3D devices but also in its remarkable material-independence that enables cross-platform solutions.This review emphasizes FsLDW fabrication of waveguide structures with 3D layouts in dielectric crystals.Their functionalities as passive and active photonic devices are also demonstrated and discussed.
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
基金supported by the National Natural Science Foundation of China(20873150)the Natural Science Foundation of Shandong Province(ZR2010BQ023)
文摘One novel cobalt coordination polymer, {[Co（HTCB）（4,4＇btb）]＇HzO}n （1, H3TCB = 1,3,5-tris（4-carboxyphenyl）benzene, 4,4＇-btb = 4,4＇-bis（1,2,4-triazol-3-yl）biphenyl）, has been synthesized and characterized by elemental analysis, IR, powder X-ray diffraction （PXRD）, and thermogravimetric （TG） analyses. X-ray diffraction analysis reveals that complex 1 is a 2D 2-fold interpenetrated {44,62}-sql [Co（HTCB）（4,4＇-btb）] sheet based on the 1D [Co（HTCB）]n chains and 1D [Co（4,4＇-btb）]n chains. The crystal of 1 crystallizes in triclinic, space group P1 with a = 9.529（12）, b = 13.914（16）, c = 14.906（17） A, V= 1903（4） A3, Z = 2, C45H34N6CoO71 Mr= 829.71, Dc = 1.448 g/cm3, F（000） = 858 andμ（MoKa） = 0.514 mm-1. The final R = 0.0655 and wR = 0.1136 for 6603 observed reflections with 1 〉 2a（/） and R = 0.1136 and wR = 0.1747 for all data.
基金the State High Technology Program for Inertial Confinement Fusion and National Science Foundation (No.59823003)Project of United Foundation (No.10676019)Youth Scientist Fund of Shandong Province (Nos. 2004BS04022 and 03BS079)
文摘During the process of KDP crystal growth, metal ions strongly affect the growth habit and optical properties of KDP single crystal. In this paper, KDP crystals were grown from an aqueous solution doped with different concentration of Fe^3＋ dopant by traditional temperaturereduction method and ＂point-seed＂ rapid growth method. Furthermore, we examined the light scatter and measured the transmission of these KDP crystals. It is found that the dopant of Fe^3＋ ion can improve the stability of the KDP growth solution when its concentration is less than 30 ppm. The effects of Fe^3＋ ion on the growth habit and optical properties of KDP crystal are also obvious.
基金Project supported by National Natural Science Foundation of China(51832007)Research and Development Project of Scientific Instruments of the Chinese Academy of Sciences(YJKYYQ20170073)Natural Science Foundation of Shandong Province(ZR2020ZD35)。
文摘The growth of high-quality and large-size cerium-doped lutetium yttrium orthosilicate(Ce:(LuY)2 SiO5,Ce:LYSO)crystals with lower cost has great influence on their applications in various physical devices.According to the chemical bonding theory of single crystal growth,the fast thermodynamic growth direction of Ce:LYSO is[010]direction.In this work,the maximum pulling rate of 3.5 mm/h is obtained along[010]direction of Ce:LYSO via the Czochralski(Cz)method.Finally,Ce:LYSO bulk single crystals with diameter of 64 mm and length of 220 mm and mass of 4.2 kg are grown.The luminescence performance of low-doped Ce:LYSO for nuclear irradiation(^(22)Na)detector device was studied.Light yield of26193 ph/MeV and decay time of 38 ns are obtained.The present work provides a promising fast growth approach to achieving large size functional bulk crystal via both thermodynamic and kinetic controls.
基金Project supported by the Fund of Key Laboratory of Optoelectronic Materials Chemistry and Physics,Chinese Academy of Sciences(Grant No.2008DP173016)the National Key Research and Development Program of China(Grant No.2016YFB1102202)the National Key Research and Development Program of China(Grant No.2016YFB0701002)
文摘Dy：Lu2O3 was grown by the float-zone （Fz） method. According to the absorption spectrum, the Judd-Ofelt （JO） parameters Ω2, Ω4, and Ω6 were calculated to be 4.86 × 10-20 cm2, 2.02 × 10-20 cm2, and 1.76 ×10-20 cm2, respectively. The emission cross-section at 574 nm corresponding to the 4F9/2 →6H13/2 transition was calculated to be 0.53 ×10 20 cm2. The yellow （4F9/2 →6H13/2 transition） to blue （4F9/2 →6H15/2 transition） intensity ratio ranges up to 12.9. The fluorescence lifetime of the 4F9/2 energy level was measured to be 112.1 μs. These results reveal that Dy：Lu2O3 is a promising material for use in yellow lasers.
基金Supported by the National Natural Science Foundation of China under Grant No 10676019.
文摘We present the characteristics of bulk damage induced by the third harmonic of Nd：YAG laser irradiation in KDP and DKDP crystals. Bulk damage occurs as a few or a series of pinpoints consisting of a core and the deforming zone. The results of a 1-on-1 test reveal that the pinpoint size increases with incvreasing fluence, and the pinpoint density increases exponentially with increasing fluence. The results of an s-on-1 test indicate that the pinpoint density increases gradually with laser pulse number, but the size does not grow. These results are consistent with a model in which nanoabsorbers are assumed to exist in the crystal and the initiation of damage is determined by heating them to the critical temperature.
基金Supported by the National Natural Science Foundation of China under Grant No 10676019
文摘By testing the number increase and size growth of surface and bulk laser induced damage in KDP and DKDP crystals, we observe different growth characteristics of surface and bulk damage under multiple 355nm laser irradiations. The size of the surface damage grows exponentially, but that of the bulk damage does not grow. In contrast, the bulk damage number increases, but that of surface damage does not increase significantly. We attribute the differences to the different formation of the damage initiators and the different damage testing volumes.
基金financially supported by the National Key R&D Program of China(No.2021YFB3502500)National Natural Science Foundation of China(Nos.22205131 and 22375115)+5 种基金Postdoctoral Innovation Project of Shandong Province(No.SDCX-ZG-202202015)Natural Science Foundation of Shandong Province(Nos.2022HYYQ-014 and ZR2023QE150)Provincial Key Research and Development Program of Shandong(No.2021ZLGX01)“20 Clauses about Colleges and Universities(new)”(Independent Training of Innovation Team)Program of Jinan(No.2021GXRC036)Qilu Young Scholar Program of Shandong University(No.31370082163127)Shenzhen municipal special fund for guiding local scientific and Technological Development(China 2021Szvup071)。
文摘Rare earth(RE)takes an irreplaceable role in various fields,especially the high-tech electronics industry,which is usually comparable to the vitamin of industry.In the development of electromagnetic wave(EMW)absorption materials,the participation of RE makes a significant contribution as well,and great progress has been made.Abundant researches have illuminated that the strategy of both doping RE elements and constructing RE oxide composites exhibited huge potential for the fabrication of high-efficiency EMW absorption materials.We believe a systematic summary will be highly desired for a comprehensive understanding and future development.In this review,we first summarized the research background,basic principles,and mechanisms of EMW absorption.Then,we classify the RE EMW absorption materials into RE-doped ferrites,RE-transition metal intermetallics,RE oxides,and other categories,view their current progress by typical studies,and expound their respective features,strengths,weaknesses,and absorption mechanisms.Finally,the current challenges and future outlook of RE EMW absorption materials are highlighted,in the hope of guidance for a sound future development.
