Ruthenium(Ru)-based chalcogenide(S,Se)is a promising material in various fields,such as optics,photoelectrodes,and electrocatalysis,owing to its suitable bandgap for generating charge carriers under light illumination...Ruthenium(Ru)-based chalcogenide(S,Se)is a promising material in various fields,such as optics,photoelectrodes,and electrocatalysis,owing to its suitable bandgap for generating charge carriers under light illumination ranging from visible to near-infrared(NIR)and its high absorption coefficient.In this study,we report the synthesis of Ru Se_(2)thin films by chemical vapor deposition(CVD)with a bandgap matching the NIR region at 0.52 e V.Further,we demonstrated Ru S_(2x)Se_(2-2x)alloy films using the post-sulfurization process after CVD Ru Se_(2)with a tunable bandgap from 0.52 to 1.39 e V depending on sulfur composition.Remarkably,Ru S_(2x)Se_(2-2x)alloy film metal–semiconductor–metal(MSM)photodetector sulfurized at 500°C,with a 0.75 e V bandgap,exhibits enhanced broad absorption across NIR spectral ranges,suppressed dark current and high photoresponsivity in NIR wavelengths range even at zero-bias.We believe the bandgaptunable Ru S_(2x)Se_(2-2x)thin film through an efficient deposition method could be suitable for various optoelectronic applications.展开更多
Van der Waals(vdW)ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching,which shows great potential to construct artificial visua...Van der Waals(vdW)ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching,which shows great potential to construct artificial visual neural systems.However,the mechanical exfoliation fabrication scheme for proof-of-concept demonstrations and fundamental studies is cumbersome and not scalable for practical application.Here,we present a synthetic strategy for the large-scale and high crystallinity growth of planar/verticalα-In_(2)Se_(3)/MoS_(2)heterojunctions by dynamically tuning the growth temperature.Furthermore,based on theα-In_(2)Se_(3)/MoS_(2)heterostructures,photo-synapse devices are designed and fabricated to simulate visual neural systems functions,including multistate storage,optical logic operation,potentiation and depression,paired-pulse facilitation(PPF),short-term memory(STM),long-term memory(LTM),and Learning-Forgetting-Relearning.By coupling the spatiotemporally relevant optical and electric information,the device can mimic the superior biological visual system’s light adaptation and Pavlovian conditioning.This work provides a strategy for dynamically tuning the orientation of ferroelectric-semiconductor heterojunction stacks and will give impetus to applying all-in-one sensing and memory-computing artificial vision systems.展开更多
Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic ...Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.展开更多
The charge density wave(CDW)state is a ubiquitous ordered phase in condensed matter systems,characterized by a periodic modulation of the electronic charge density.In many CDW materials,superconductivity(SC)emerges in...The charge density wave(CDW)state is a ubiquitous ordered phase in condensed matter systems,characterized by a periodic modulation of the electronic charge density.In many CDW materials,superconductivity(SC)emerges in close proximity to,or coexists with,the CDW phase,offering a valuable platform to explore the interplay between these two competing orders.The ZrTe_(3-x)Se_(x)family provides an ideal system for investigating this interplay,as both CDW-dominated and superconductivity-dominated end members have been well studied,while the intermediate compositions remain largely unexplored.In this study,we employ high-resolution angle-resolved photoemission spectroscopy(ARPES)to systematically investigate the band structure and CDW gap in Se-doped ZrTe_(3-x)Se_(x)(x=0.015),a prototypical system exhibiting the coexistence of CDW and superconductivity phases.Detailed analysis of the band structure across the Brillouin zone reveals highly momentum-dependent,anisotropic CDW gaps.Quasi-2D Fermi surface centered at F exhibits the absence of CDW gap,while on quasi-1D Fermi surface along the Brillouin zone boundary,there is also a highly anisotropic distribution of CDW gap.The gap is zero at B,while reaching its maximum at a nesting vector consistent with the bulk CDW modulation.These results provide direct evidence that quasi-1D Fermi surface nesting is the primary driving force behind CDW formation in this compound.Notably,our measurements reveal a strongly suppressed density of state around EFeven out of CDW gap and absence of band folding induced by Fermi surface nesting.This observation suggests that selenium doping enhances fluctuations of the CDW order parameter,thereby weakening the long-range CDW coherence.Such enhanced fluctuations are likely to facilitate SC pairing,contributing to the observed increase in the SC transition temperature of the doped samples.Our findings not only provide comprehensive understanding of the CDW state in the ZrTe_(3-x)Se_(x)family but also demonstrate that chemical doping provides an effective route to tune the competition between CDW and superconductivity.展开更多
The structural design of n-i-p in antimony selenide(Sb_(2)Se_(3))thin film solar cells can effectively improve the low carrier collection efficiency caused by the lower doping concentration of Sb_(2)Se_(3).However,the...The structural design of n-i-p in antimony selenide(Sb_(2)Se_(3))thin film solar cells can effectively improve the low carrier collection efficiency caused by the lower doping concentration of Sb_(2)Se_(3).However,the unideal carrier transport ability of the intrinsic light-absorbing layer remains a major limitation for its power conversion efficiency improvement.Herein,it is discovered that the carrier transport in Sb_(2)Se_(3)thin films strongly depends on the film thickness of the absorber layer in n-i-p structure.By exploring the carrier transport mechanism under different thicknesses of light-absorbing layers,a suitable absorber layer with thickness of 550 nm is demonstrated can effectively separate,transport,and extract photogenerated carriers in Sb_(2)Se_(3)solar cells.Finally,the vapor transport deposition processed Sb_(2)Se_(3)solar cells achieve the highest PCE of 7.62%with a short-circuit current density of 30.71 mA·cm^(-2).This finding provides a constructive guidance for the future researches on Sb_(2)Se_(3)thin film solar cells with n-i-p structure.展开更多
Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device pe...Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device performance,as in a wide bandgap Zn_(1-x)Mg_(x)O(ZMO)to replace the CdS buffer in Cu(In_(1-x),Ga_(x))Se_(2)(CIGSe)thin-film solar cell structure.ZMO is one of the candidates for the buffer material in CIGSe thin-film solar cells with a wide and controllable bandgap depending on the Mg content,which can be helpful in attaining a suitable conduction band offset.Hence,compared to the fixed and limited bandgap of a CdS buffer,a ZMO buffer may provide advantages in V_(oc) and J_(sc) based on its controllable and wide bandgap,even with a relatively wider bandgap CIGSe thin-film solar cell.In addition,to solve problems with the defect sites at the ZMO/CIGSe junction interface,a few-nanometer ZnS layer is employed for heterojunction interface passivation,forming a ZMO/ZnS buffer structure by atomic layer deposition(ALD).Finally,a Cd-free all-dry-processed CIGSe solar cell with a wider bandgap(1.25 eV)and ALD-grown buffer structure exhibited the best power conversion efficiency of 19.1%,which exhibited a higher performance than the CdS counterpart.展开更多
基于像差校正扫描透射电子显微学和第一性原理计算,研究了van der Waals(范德瓦尔斯)层状β-In_(2)Se_(3)中堆垛缺陷的原子构型。结果表明,在2Hβ-In_(2)Se_(3)中存在大量的置换型层错(RSF)和滑移型层错(SSF),发现了一种在热力学上易自...基于像差校正扫描透射电子显微学和第一性原理计算,研究了van der Waals(范德瓦尔斯)层状β-In_(2)Se_(3)中堆垛缺陷的原子构型。结果表明,在2Hβ-In_(2)Se_(3)中存在大量的置换型层错(RSF)和滑移型层错(SSF),发现了一种在热力学上易自发形成的T相滑移型堆垛层错(tSSF);在3Rβ-In_(2)Se_(3)中只观察到一种能量较高的滑移型层错;2H和3Rβ-In_(2)Se_(3)以界面连续过渡的方式发生相分离。本文还构建9种β-In_(2)Se_(3)潜在的堆垛层错构型,并计算了相应的堆垛层错能并从能量角度分析了堆垛层错的成因。最后,指出建立分类术语描述类van der Waals层状材料堆垛层错的必要性。展开更多
基金supported by TANAKA KIKINZOKU KOGYO K.Kfinancially supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2022R1A2C2006764)the Materials and Components Technology Development Program of MOTIE/KEIT(No.[20012460])。
文摘Ruthenium(Ru)-based chalcogenide(S,Se)is a promising material in various fields,such as optics,photoelectrodes,and electrocatalysis,owing to its suitable bandgap for generating charge carriers under light illumination ranging from visible to near-infrared(NIR)and its high absorption coefficient.In this study,we report the synthesis of Ru Se_(2)thin films by chemical vapor deposition(CVD)with a bandgap matching the NIR region at 0.52 e V.Further,we demonstrated Ru S_(2x)Se_(2-2x)alloy films using the post-sulfurization process after CVD Ru Se_(2)with a tunable bandgap from 0.52 to 1.39 e V depending on sulfur composition.Remarkably,Ru S_(2x)Se_(2-2x)alloy film metal–semiconductor–metal(MSM)photodetector sulfurized at 500°C,with a 0.75 e V bandgap,exhibits enhanced broad absorption across NIR spectral ranges,suppressed dark current and high photoresponsivity in NIR wavelengths range even at zero-bias.We believe the bandgaptunable Ru S_(2x)Se_(2-2x)thin film through an efficient deposition method could be suitable for various optoelectronic applications.
基金supported by the National Natural Science Foundation of China(Nos.52371245,12174237,12241403)the National Key Research and Development Program of China(No.2022YFB3505301).
文摘Van der Waals(vdW)ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching,which shows great potential to construct artificial visual neural systems.However,the mechanical exfoliation fabrication scheme for proof-of-concept demonstrations and fundamental studies is cumbersome and not scalable for practical application.Here,we present a synthetic strategy for the large-scale and high crystallinity growth of planar/verticalα-In_(2)Se_(3)/MoS_(2)heterojunctions by dynamically tuning the growth temperature.Furthermore,based on theα-In_(2)Se_(3)/MoS_(2)heterostructures,photo-synapse devices are designed and fabricated to simulate visual neural systems functions,including multistate storage,optical logic operation,potentiation and depression,paired-pulse facilitation(PPF),short-term memory(STM),long-term memory(LTM),and Learning-Forgetting-Relearning.By coupling the spatiotemporally relevant optical and electric information,the device can mimic the superior biological visual system’s light adaptation and Pavlovian conditioning.This work provides a strategy for dynamically tuning the orientation of ferroelectric-semiconductor heterojunction stacks and will give impetus to applying all-in-one sensing and memory-computing artificial vision systems.
基金financially supported by the National Natural Science Foundation of China(22278348)Natural Science Foundation of Xinjiang Autonomous Region(2022D01D05)+1 种基金National guidance for local projects of Xinjiang Autonomous Region(ZYYD2025JD09)Tianshan Leading technology talents Program of Xinjiang Autonomous Region。
文摘Sodium-ion batteries(SIBs)show promising potential in the field of electrochemical energy storage due to their cost-effectiveness and similar operational mechanisms to lithium-ion batteries(LIBs).However,the dramatic volume expansion of electrode materials and the slow reaction kinetics caused by the large sodium ion(Na^(+))radius hinder the practical application of SIBs,Here,we successfully prepared SnS_(2-x)Se_(x)nanodots embedded within N-doped carbon nanofibers(CNF)for use as electrode materials of SIBs,The introduction Se provided abundant anionic defect sites for Na+storage and enlarged the interlayer spacing of SnS_(2).In addition,the ultraifne nanodot structure reduces the volume expansion of SnS_(2-x)Se_(x)and shortens the ion transport path.As an anode of SIBs,SnS_(2-x)Se_(x)/CNF demonstrates remarkable reversible capacity(719 mAh g^(-1)at 0.5 A g^(-1)),along with rapid charging ability(completing a charge in just 127 s).Meanwhile,the assembled full-cell battery manifested exceptional energy density of 165.8 Wh kg^(-1)at a high-power output of 5526 W kg^(-1).This study presents an effective strategy for fabricating highperformance sulphide-based anode materials for SIBs,offering broad prospects for application.
基金support from the National Key R&D Program of China(Grant No.2023YFA1407400)the National Natural Science Foundation of China(Grant No.12374063)+4 种基金the National Natural Science Foundation of China(GrantNo.12488101)the Shanghai Natural Science Fund for Original Exploration Program(Grant No.23ZR1479900)the Cultivation Project of Shanghai Research Center for Quantum Sciences(Grant No.LZPY2024)support from the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0302700)the New Cornerstone Science Foundation(Grant No.23H010801236)。
文摘The charge density wave(CDW)state is a ubiquitous ordered phase in condensed matter systems,characterized by a periodic modulation of the electronic charge density.In many CDW materials,superconductivity(SC)emerges in close proximity to,or coexists with,the CDW phase,offering a valuable platform to explore the interplay between these two competing orders.The ZrTe_(3-x)Se_(x)family provides an ideal system for investigating this interplay,as both CDW-dominated and superconductivity-dominated end members have been well studied,while the intermediate compositions remain largely unexplored.In this study,we employ high-resolution angle-resolved photoemission spectroscopy(ARPES)to systematically investigate the band structure and CDW gap in Se-doped ZrTe_(3-x)Se_(x)(x=0.015),a prototypical system exhibiting the coexistence of CDW and superconductivity phases.Detailed analysis of the band structure across the Brillouin zone reveals highly momentum-dependent,anisotropic CDW gaps.Quasi-2D Fermi surface centered at F exhibits the absence of CDW gap,while on quasi-1D Fermi surface along the Brillouin zone boundary,there is also a highly anisotropic distribution of CDW gap.The gap is zero at B,while reaching its maximum at a nesting vector consistent with the bulk CDW modulation.These results provide direct evidence that quasi-1D Fermi surface nesting is the primary driving force behind CDW formation in this compound.Notably,our measurements reveal a strongly suppressed density of state around EFeven out of CDW gap and absence of band folding induced by Fermi surface nesting.This observation suggests that selenium doping enhances fluctuations of the CDW order parameter,thereby weakening the long-range CDW coherence.Such enhanced fluctuations are likely to facilitate SC pairing,contributing to the observed increase in the SC transition temperature of the doped samples.Our findings not only provide comprehensive understanding of the CDW state in the ZrTe_(3-x)Se_(x)family but also demonstrate that chemical doping provides an effective route to tune the competition between CDW and superconductivity.
基金supported by the National Natural Science Foundation of China(No.62305064)the Beijing Nova Program from Beijing Municipal Science&Technology Commission(No.Z211100002121072).
文摘The structural design of n-i-p in antimony selenide(Sb_(2)Se_(3))thin film solar cells can effectively improve the low carrier collection efficiency caused by the lower doping concentration of Sb_(2)Se_(3).However,the unideal carrier transport ability of the intrinsic light-absorbing layer remains a major limitation for its power conversion efficiency improvement.Herein,it is discovered that the carrier transport in Sb_(2)Se_(3)thin films strongly depends on the film thickness of the absorber layer in n-i-p structure.By exploring the carrier transport mechanism under different thicknesses of light-absorbing layers,a suitable absorber layer with thickness of 550 nm is demonstrated can effectively separate,transport,and extract photogenerated carriers in Sb_(2)Se_(3)solar cells.Finally,the vapor transport deposition processed Sb_(2)Se_(3)solar cells achieve the highest PCE of 7.62%with a short-circuit current density of 30.71 mA·cm^(-2).This finding provides a constructive guidance for the future researches on Sb_(2)Se_(3)thin film solar cells with n-i-p structure.
基金conducted under the framework of the research and development program of the Korea Institute of Energy Research(C4-2412 and C4-2413)supported by the National Research Foundation of Korea(grant number 2022M3J1A1063019)funded by the Ministry of Science and ICT.
文摘Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device performance,as in a wide bandgap Zn_(1-x)Mg_(x)O(ZMO)to replace the CdS buffer in Cu(In_(1-x),Ga_(x))Se_(2)(CIGSe)thin-film solar cell structure.ZMO is one of the candidates for the buffer material in CIGSe thin-film solar cells with a wide and controllable bandgap depending on the Mg content,which can be helpful in attaining a suitable conduction band offset.Hence,compared to the fixed and limited bandgap of a CdS buffer,a ZMO buffer may provide advantages in V_(oc) and J_(sc) based on its controllable and wide bandgap,even with a relatively wider bandgap CIGSe thin-film solar cell.In addition,to solve problems with the defect sites at the ZMO/CIGSe junction interface,a few-nanometer ZnS layer is employed for heterojunction interface passivation,forming a ZMO/ZnS buffer structure by atomic layer deposition(ALD).Finally,a Cd-free all-dry-processed CIGSe solar cell with a wider bandgap(1.25 eV)and ALD-grown buffer structure exhibited the best power conversion efficiency of 19.1%,which exhibited a higher performance than the CdS counterpart.
文摘基于像差校正扫描透射电子显微学和第一性原理计算,研究了van der Waals(范德瓦尔斯)层状β-In_(2)Se_(3)中堆垛缺陷的原子构型。结果表明,在2Hβ-In_(2)Se_(3)中存在大量的置换型层错(RSF)和滑移型层错(SSF),发现了一种在热力学上易自发形成的T相滑移型堆垛层错(tSSF);在3Rβ-In_(2)Se_(3)中只观察到一种能量较高的滑移型层错;2H和3Rβ-In_(2)Se_(3)以界面连续过渡的方式发生相分离。本文还构建9种β-In_(2)Se_(3)潜在的堆垛层错构型,并计算了相应的堆垛层错能并从能量角度分析了堆垛层错的成因。最后,指出建立分类术语描述类van der Waals层状材料堆垛层错的必要性。
