As the lastly unexplored electromagnetic wave,terahertz(THz)radiation has been exploited in a plenty of contexts such as fundamental research,military and civil fields.Most recently,representative two-dimensional(2D)t...As the lastly unexplored electromagnetic wave,terahertz(THz)radiation has been exploited in a plenty of contexts such as fundamental research,military and civil fields.Most recently,representative two-dimensional(2D)topological semimetal,platinum ditelluride(PtTe_(2))has attracted considerable research interest in THz detection due to its unique physical properties.However,to achieve practical applications,the low-cost,large-scale,controllable synthesis and efficient patterning of 2D materials are key requirements,which remain a challenge for PtTe_(2)and its photodetectors(PDs).Herein,a facile approach is developed to obtain waferscale(2-inches)patterned PtTe_(2)arrays using one-step tellurium-vapor transformation method and micro-Nano technology.PtTe_(2)PD arrays are fabricated with the as-grown PtTe_(2)arrays evenly distributed on a 2-inch wafer,exhibiting high conductivity(~2.7×105 S m^(-1))and good electrical consistency.Driven by the Dirac fermions,PtTe_(2)PDs achieve a broadband(0.02-0.3 THz)response with a fast response speed(~4.7μs),a high sensitivity(~47 pW Hz^(-1/2))and high-resolution transmission THz-imaging capability,which displays the potential of large-area THz array imaging.These results are one step towards the practical applications of integrated PD arrays based on 2D materials.展开更多
Dimethyl oxalate(DMO) hydrogenation is a crucial step in the coal to ethylene glycol(CTEG) process.Herein, Cu catalyst supported on fibrous mesoporous silica(Cu/FMS) was synthesized via liquid phase deposition techniq...Dimethyl oxalate(DMO) hydrogenation is a crucial step in the coal to ethylene glycol(CTEG) process.Herein, Cu catalyst supported on fibrous mesoporous silica(Cu/FMS) was synthesized via liquid phase deposition technique and applied for the DMO hydrogenation to EG. The catalyst exhibited a remarkable EG selectivity of 96.95% and maintained its activity without deactivation for 1000 h. Fibers of FMS support and liquid phase deposition technology cooperated to give high dispersion of Cu species in the Cu/FMS catalyst, resulting in a high Cu surface area. The formation of Si—O—Cu during catalyst preparation process increased the Cu^(+)/(Cu^(0)+ Cu^(+)) ratio and enhanced the thermal and valence stability of Cu species.The high Cu^(+) surface area and Cu stability(thermal and valence stability) of the Cu/FMS catalyst were key factors for achieving superior EG selectivity and ultra-high stability.展开更多
Two-dimensional(2D)black phosphorus(BP)has attracted great attention in recent years in fundamental research as well as optoelectronics applications.The controllable synthesis of high-quality BP is vital to the invest...Two-dimensional(2D)black phosphorus(BP)has attracted great attention in recent years in fundamental research as well as optoelectronics applications.The controllable synthesis of high-quality BP is vital to the investigation of its intrinsic physical properties and versatile applications.Originally,BP was mostly synthesized under high temperatures and pressures.Subsequently,metal flux,wet chemical and chemical vapor transport(CVT)methods had been appeared successively.The pulsed laser deposition(PLD)and CVT methods have been used to prepare high-quality BP thin films on silicon substrates,which is significant for its monolithic integration and practical applications.To meet the demand of the scalable applications of BP,the direct preparation of BP films on dielectric substrates that avoids additional transfer process,is crucial to high-performance device implementation.In this review,the growing methods and corresponding mechanisms of BP are summarized and analyzed.Meanwhile,the view on the controllable growth of large-area,high-quality BP films is envisioned.展开更多
We report a single-frequency linearly polarized Q-switched fiber laser based on an Nb_(2)GeTe_(4)saturable absorber(SA).The Nb_(2)GeTe_(4)SA triggers passive Q-switching of the laser,and an un-pumped Yb-doped fiber to...We report a single-frequency linearly polarized Q-switched fiber laser based on an Nb_(2)GeTe_(4)saturable absorber(SA).The Nb_(2)GeTe_(4)SA triggers passive Q-switching of the laser,and an un-pumped Yb-doped fiber together with a 0.08-nmbandwidth polarization-maintaining fiber Bragg grating(FBG)acts as an ultra-narrow bandwidth filter to realize singlelongitudinal-mode(SLM)oscillation.The devices used in the laser are all kept polarized,so as to ensure linearly polarized laser output.Stable SLM linearly polarized Q-switching operation at 1064.6 nm is successfully achieved,producing a laser with a shortest pulse width of 1.36μs,a linewidth of 28.4 MHz,a repetition rate of 28.3 kHz-95.9 kHz,and a polarization extinction ratio of about 30 dB.It is believed that the single-frequency linearly polarized pulsed fiber laser studied in this paper has great application value in gravitational wave detection,beam combining,nonlinear frequency conversion,and other fields.展开更多
多层黑磷的带隙(~0.33 eV)覆盖~3.7微米光谱范围,在红外应用方面有巨大潜力.然而进一步降低带隙使其可用于远红外器件仍面临挑战.此外,黑磷材料及器件饱受空气稳定性差的困扰.因此,我们提出了同系物砷取代的策略,实现了对黑磷带隙的调...多层黑磷的带隙(~0.33 eV)覆盖~3.7微米光谱范围,在红外应用方面有巨大潜力.然而进一步降低带隙使其可用于远红外器件仍面临挑战.此外,黑磷材料及器件饱受空气稳定性差的困扰.因此,我们提出了同系物砷取代的策略,实现了对黑磷带隙的调控和稳定性的增强.通过优化化学气相传输的生长参数,我们制备出砷含量可控的毫米级黑磷母体.经扫描隧道显微镜和能谱分析,砷原子随机嵌入黑磷的主晶格中并保留了原有几近完美的晶格排列.对于60%砷含量的多层黑磷,其电学带隙降低至~0.16±0.02 eV并伴随强的p型掺杂.受益于较小的晶格畸变和强掺杂效应,基于砷取代黑磷的光电器件表现出高达约882 mA W^(-1)的光响应率,远超未取代的黑磷基光电器件(约314 mA W^(-1)).更为重要的是,砷取代的黑磷器件在暴露大气环境(温度~20℃;湿度~33%)48小时后未表现出明显的氧化迹象.本文为开发黑磷基、可长时间运行的光电探测器和光调制器件提供了新途径.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:61875223,61922082,61927813National Key R&D Program of China,Grant/Award Number:2021YFB2800702+3 种基金Jiangsu Province Key R&D Program,Grant/Award Numbers:BE2021007-3,BE2021007-2Shanghai Municipal Science and Technology Major Project,Grant/Award Number:2019SHZDZX01Science and Technology Commission of Shanghai Municipality,Grant/Award Number:21ZR1473800Vacuum Interconnected Nanotech Workstation(Nano-X)of Suzhou Institute of Nano-tech and Nano-bionics(SINANO),Chinese Academy of Sciences。
文摘As the lastly unexplored electromagnetic wave,terahertz(THz)radiation has been exploited in a plenty of contexts such as fundamental research,military and civil fields.Most recently,representative two-dimensional(2D)topological semimetal,platinum ditelluride(PtTe_(2))has attracted considerable research interest in THz detection due to its unique physical properties.However,to achieve practical applications,the low-cost,large-scale,controllable synthesis and efficient patterning of 2D materials are key requirements,which remain a challenge for PtTe_(2)and its photodetectors(PDs).Herein,a facile approach is developed to obtain waferscale(2-inches)patterned PtTe_(2)arrays using one-step tellurium-vapor transformation method and micro-Nano technology.PtTe_(2)PD arrays are fabricated with the as-grown PtTe_(2)arrays evenly distributed on a 2-inch wafer,exhibiting high conductivity(~2.7×105 S m^(-1))and good electrical consistency.Driven by the Dirac fermions,PtTe_(2)PDs achieve a broadband(0.02-0.3 THz)response with a fast response speed(~4.7μs),a high sensitivity(~47 pW Hz^(-1/2))and high-resolution transmission THz-imaging capability,which displays the potential of large-area THz array imaging.These results are one step towards the practical applications of integrated PD arrays based on 2D materials.
基金financially supported by National Natural Science Foundation of China (22008166)Natural Science Foundation of Shanxi (201901D211047)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (2019L0185)。
文摘Dimethyl oxalate(DMO) hydrogenation is a crucial step in the coal to ethylene glycol(CTEG) process.Herein, Cu catalyst supported on fibrous mesoporous silica(Cu/FMS) was synthesized via liquid phase deposition technique and applied for the DMO hydrogenation to EG. The catalyst exhibited a remarkable EG selectivity of 96.95% and maintained its activity without deactivation for 1000 h. Fibers of FMS support and liquid phase deposition technology cooperated to give high dispersion of Cu species in the Cu/FMS catalyst, resulting in a high Cu surface area. The formation of Si—O—Cu during catalyst preparation process increased the Cu^(+)/(Cu^(0)+ Cu^(+)) ratio and enhanced the thermal and valence stability of Cu species.The high Cu^(+) surface area and Cu stability(thermal and valence stability) of the Cu/FMS catalyst were key factors for achieving superior EG selectivity and ultra-high stability.
基金supported by the National Key R&D Program of China(No.2021YFA1200804)the National Natural Science Foundation of China(Grant Nos.61922082,61875223,and 61927813)The support from the Vacuum Interconnected Nanotech Workstation(Nano-X)of Suzhou Institute of Nano-tech and Nanobionics(SINANO),Chinese Academy of Sciences is also acknowledged.
文摘Two-dimensional(2D)black phosphorus(BP)has attracted great attention in recent years in fundamental research as well as optoelectronics applications.The controllable synthesis of high-quality BP is vital to the investigation of its intrinsic physical properties and versatile applications.Originally,BP was mostly synthesized under high temperatures and pressures.Subsequently,metal flux,wet chemical and chemical vapor transport(CVT)methods had been appeared successively.The pulsed laser deposition(PLD)and CVT methods have been used to prepare high-quality BP thin films on silicon substrates,which is significant for its monolithic integration and practical applications.To meet the demand of the scalable applications of BP,the direct preparation of BP films on dielectric substrates that avoids additional transfer process,is crucial to high-performance device implementation.In this review,the growing methods and corresponding mechanisms of BP are summarized and analyzed.Meanwhile,the view on the controllable growth of large-area,high-quality BP films is envisioned.
基金Project supported by the National Natural Science Foundation of China(Grant No.62275272)the Training Program for Excellent Young Innovators of Changsha,China(Grant No.KQ2206003).
文摘We report a single-frequency linearly polarized Q-switched fiber laser based on an Nb_(2)GeTe_(4)saturable absorber(SA).The Nb_(2)GeTe_(4)SA triggers passive Q-switching of the laser,and an un-pumped Yb-doped fiber together with a 0.08-nmbandwidth polarization-maintaining fiber Bragg grating(FBG)acts as an ultra-narrow bandwidth filter to realize singlelongitudinal-mode(SLM)oscillation.The devices used in the laser are all kept polarized,so as to ensure linearly polarized laser output.Stable SLM linearly polarized Q-switching operation at 1064.6 nm is successfully achieved,producing a laser with a shortest pulse width of 1.36μs,a linewidth of 28.4 MHz,a repetition rate of 28.3 kHz-95.9 kHz,and a polarization extinction ratio of about 30 dB.It is believed that the single-frequency linearly polarized pulsed fiber laser studied in this paper has great application value in gravitational wave detection,beam combining,nonlinear frequency conversion,and other fields.
基金supported by the Postgraduate Research and Practice Innovation Program of NUAA(xcxjh20210111)the National Natural Science Foundation of China(1210040808,61922082,and 12004180)+5 种基金the National Key Research and Development Program of China(2019YFA0705400)the Natural Science Foundation of Jiangsu Province(BK20210312 and BK20190018)the Fundamental Research Funds for the Central Universities(NS2020008 and NJ2019002)the Program for Innovative Talents and Entrepreneur in Jiangsuthe Research Fund for the State Key Laboratory of Mechanics and Control of Mechanical Structures(MCMS-I-0419G02)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘多层黑磷的带隙(~0.33 eV)覆盖~3.7微米光谱范围,在红外应用方面有巨大潜力.然而进一步降低带隙使其可用于远红外器件仍面临挑战.此外,黑磷材料及器件饱受空气稳定性差的困扰.因此,我们提出了同系物砷取代的策略,实现了对黑磷带隙的调控和稳定性的增强.通过优化化学气相传输的生长参数,我们制备出砷含量可控的毫米级黑磷母体.经扫描隧道显微镜和能谱分析,砷原子随机嵌入黑磷的主晶格中并保留了原有几近完美的晶格排列.对于60%砷含量的多层黑磷,其电学带隙降低至~0.16±0.02 eV并伴随强的p型掺杂.受益于较小的晶格畸变和强掺杂效应,基于砷取代黑磷的光电器件表现出高达约882 mA W^(-1)的光响应率,远超未取代的黑磷基光电器件(约314 mA W^(-1)).更为重要的是,砷取代的黑磷器件在暴露大气环境(温度~20℃;湿度~33%)48小时后未表现出明显的氧化迹象.本文为开发黑磷基、可长时间运行的光电探测器和光调制器件提供了新途径.
