The electric and dielectric properties of metalloprotein, azurin, were studied at real molecular level by using conducting atomic force microscopy(C-AFM). Under a force lower than 2 nN, dielectric breakdown was observ...The electric and dielectric properties of metalloprotein, azurin, were studied at real molecular level by using conducting atomic force microscopy(C-AFM). Under a force lower than 2 nN, dielectric breakdown was observed. When reliable electrical contact between electrodes and protein is achieved under a force greater than 5 nN, well-behaved current-voltage characters are revealed, and dependent on the force load.展开更多
The study of size effect of conductivity of conducting polymer nanowires can be significant not only in the instruction of fabrication of the devices with nanodimension but also in basic research of inherence of nanom...The study of size effect of conductivity of conducting polymer nanowires can be significant not only in the instruction of fabrication of the devices with nanodimension but also in basic research of inherence of nanomaterials. PANI nanowires was fabricated in AAO templates by potentiostatic method. A new strategy of chemical modification of AAO template was introduced to prepare nanowires with smaller diameter. FTIR and contact angle measurements were used to characterize the modification. Tunneling Electron Microscopy results showed that the smaller PANI nanowires in diameter can be obtained in surfactant modified AAO templates. Conductivity of single PANI nanowire had been measured by Conductive Atomic Force Microscopy. The results displayed that the conductivity of PANI nanowire increase while the decrease of the diameter of PANI nanowires, which was called size effect of conductivity of PANI nanowires. The size effect had been attributed to order polymer chains orientation of PANI nanowire, which had been confirmed by electron diffraction diagrams.展开更多
钨和钼材料具有高熔点、高热导率、低溅射率等优点成为国际热核实验反应堆计划中面向等离子体材料的候选材料。因此研究钨和钼材料的辐照损伤行为对于认识面向等离子体材料的辐照损伤机制具有重要意义。本文采用120 e V的He+在873 K对...钨和钼材料具有高熔点、高热导率、低溅射率等优点成为国际热核实验反应堆计划中面向等离子体材料的候选材料。因此研究钨和钼材料的辐照损伤行为对于认识面向等离子体材料的辐照损伤机制具有重要意义。本文采用120 e V的He+在873 K对钨和钼材料进行辐照实验,利用纳米压痕仪与导电模式原子力显微镜(Conductive Atomic Force Microscopy,CAFM)相结合,原位比较了钨和钼材料在辐照前后的表面形貌、表面微结构以及表层缺陷分布的变化特征。结果表明,低能He+辐照会导致钨和钼材料的近表面产生纳米量级氦泡缺陷,这些氦泡缺陷的存在使得样品表面产生绒毛或波浪状结构。纳米压痕深度分析和扫描电镜的分析结果表明,低能He+辐照会对Mo材料产生明显的刻蚀作用。本工作对于进一步认识低能氦离子辐照对面向等离子体材料的辐照损伤作用具有一定的科学参考意义。展开更多
Atomically thin transition-metal dichalcogenide(TMDC) nanostructures are predicted to exhibit novel physical properties that make them attractive candidates for the fabrication of electronic and optoelectronic devices...Atomically thin transition-metal dichalcogenide(TMDC) nanostructures are predicted to exhibit novel physical properties that make them attractive candidates for the fabrication of electronic and optoelectronic devices. However, TMDCs tend to grow in the form of two-dimensional nanoplates(NPs) rather than one-dimensional nanoribbons(NRs) due to their native layered structure. Herein, we have developed a space-confined and substrate-directed chemical vapor deposition strategy for the controllable synthesis of WS2, WSe2, MoSe2, MoS2, WS2(1-x)Se2x NPs and NRs. TMDC NRs with lengths ranging from several micrometers to 100 μm have been obtained and the widths of TMDC NRs can be effectively tuned.Moreover, we found that TMDC NRs show different growth behaviors on van der Waals(vdW) and nonvd W substrates. The micro-nano structures, optical and electronic properties of synthesized TMDC NRs have been systematically investigated. This approach provides a general strategy for controllable synthesis of TMDC NRs, which makes these materials easily accessible as functional building blocks for novel optoelectronic devices.展开更多
利用低能H离子对20 Me V W^(6+)预注入和未注入的钨样品进行辐照实验,考察H离子能量(20-520 e V)和辐照温度(673-1073 K)变化对钨表面微结构的影响。采用非破坏性的导电模式原子力显微镜和扫描电镜分析预注入和未注入钨样品的表面形貌...利用低能H离子对20 Me V W^(6+)预注入和未注入的钨样品进行辐照实验,考察H离子能量(20-520 e V)和辐照温度(673-1073 K)变化对钨表面微结构的影响。采用非破坏性的导电模式原子力显微镜和扫描电镜分析预注入和未注入钨样品的表面形貌和内表面缺陷分布情况。结果表明,辐照后的样品表面出现大量的纳米尺寸凸起,高能W^(6+)预注入的样品表面损伤要小于未注入的钨样品,意味着高能离子预注入会对材料的表面损伤起到抑制作用,但是当辐照温度高于1073 K时,这种抑制作用开始减弱。展开更多
钼(Mo)材料被作为托卡马克装置中面向等离子体材料的候选材料被广泛研究,因此研究钼材料的辐照损伤行为对于认识聚变堆关键材料的辐照损伤机制具有重要意义。采用低能(100 e V)、大流强(约1021 ions·m-2·s-1)He+在600 oC对钼...钼(Mo)材料被作为托卡马克装置中面向等离子体材料的候选材料被广泛研究,因此研究钼材料的辐照损伤行为对于认识聚变堆关键材料的辐照损伤机制具有重要意义。采用低能(100 e V)、大流强(约1021 ions·m-2·s-1)He+在600 oC对钼样品进行辐照实验,考察了离子辐照剂量和退火温度变化对钼材料的表面损伤作用。分别采用扫描电镜(Scanning Electron Microscope,SEM)和无损伤的导电原子力显微镜(Conductive Atomic Force Microscopy,CAFM)检测技术对辐照前后样品的微观形貌、微结构演化以及内表面缺陷分布等进行了对比研究。结果表明,He+辐照会诱导钼样品晶粒尺寸的增加,钼材料表面的晶粒取向会影响辐照缺陷的分布。这对于探索抑制材料辐照损伤的新方法具有重要的指导意义。展开更多
PANI nanodots array was fabricated in AAO template with potentiostatic method in a short time.The topographic image of PANI nanodots array was characterized by scanning electron microscopy(SEM) and atomic force micros...PANI nanodots array was fabricated in AAO template with potentiostatic method in a short time.The topographic image of PANI nanodots array was characterized by scanning electron microscopy(SEM) and atomic force microscopy(AFM).The I-V characteristics of conducting PANI nanodots array was measured with conducting atomic force microscope(C-AFM) in atmosphere at room temperature.Coulomb staircase phenomena was observed in the I-V curves.展开更多
The kesterite-structured semiconductor Cu_2 Zn Sn(S,Se)_4(CZTSSe) is prepared by spin coating a non-hydrazine precursor and annealing at Se atmosphere. Local electrical and optoelectronic properties of the CZTSSe thin...The kesterite-structured semiconductor Cu_2 Zn Sn(S,Se)_4(CZTSSe) is prepared by spin coating a non-hydrazine precursor and annealing at Se atmosphere. Local electrical and optoelectronic properties of the CZTSSe thin-film are explored by Kelvin probe force microscopy and conductive atomic force microscopy. Before and after irradiation, no marked potential bending and very low current flow are observed at GBs, suggesting that GBs behave as a charge recombination site and an obstacle for charge transport. Furthermore, Cd S nano-islands are synthesized via successive ionic layer adsorption and reaction(SILAR) method on the surface of CZTSSe. By comparing the work function and current flow change of CZTSSe and Cd S in dark and under illumination, we demonstrate photo-induced electrons and holes are separated at the interface of p-n junction and transferred in Cd S and CZTSSe, respectively.展开更多
文摘The electric and dielectric properties of metalloprotein, azurin, were studied at real molecular level by using conducting atomic force microscopy(C-AFM). Under a force lower than 2 nN, dielectric breakdown was observed. When reliable electrical contact between electrodes and protein is achieved under a force greater than 5 nN, well-behaved current-voltage characters are revealed, and dependent on the force load.
文摘The study of size effect of conductivity of conducting polymer nanowires can be significant not only in the instruction of fabrication of the devices with nanodimension but also in basic research of inherence of nanomaterials. PANI nanowires was fabricated in AAO templates by potentiostatic method. A new strategy of chemical modification of AAO template was introduced to prepare nanowires with smaller diameter. FTIR and contact angle measurements were used to characterize the modification. Tunneling Electron Microscopy results showed that the smaller PANI nanowires in diameter can be obtained in surfactant modified AAO templates. Conductivity of single PANI nanowire had been measured by Conductive Atomic Force Microscopy. The results displayed that the conductivity of PANI nanowire increase while the decrease of the diameter of PANI nanowires, which was called size effect of conductivity of PANI nanowires. The size effect had been attributed to order polymer chains orientation of PANI nanowire, which had been confirmed by electron diffraction diagrams.
文摘钨和钼材料具有高熔点、高热导率、低溅射率等优点成为国际热核实验反应堆计划中面向等离子体材料的候选材料。因此研究钨和钼材料的辐照损伤行为对于认识面向等离子体材料的辐照损伤机制具有重要意义。本文采用120 e V的He+在873 K对钨和钼材料进行辐照实验,利用纳米压痕仪与导电模式原子力显微镜(Conductive Atomic Force Microscopy,CAFM)相结合,原位比较了钨和钼材料在辐照前后的表面形貌、表面微结构以及表层缺陷分布的变化特征。结果表明,低能He+辐照会导致钨和钼材料的近表面产生纳米量级氦泡缺陷,这些氦泡缺陷的存在使得样品表面产生绒毛或波浪状结构。纳米压痕深度分析和扫描电镜的分析结果表明,低能He+辐照会对Mo材料产生明显的刻蚀作用。本工作对于进一步认识低能氦离子辐照对面向等离子体材料的辐照损伤作用具有一定的科学参考意义。
基金supported by the National Natural Science Foundation of China(11974301,11404274,11574395,11702236,61804050)the support from National Natural Science Foundation of China(21673054 and 11874130)+4 种基金the Science and Technology Project of Hunan Province(2019JJ30021,2018JJ3489)Grant from Education Commission of Hunan Province(18B084)Degree and Postgraduate Education Reform Project of Hunan Province(JG2018B045)the Program for Changjiang Scholars and Innovative Research Team in University(IRT13093)financial support from the research project of National University of Defense Technology(ZK18-03-38)。
文摘Atomically thin transition-metal dichalcogenide(TMDC) nanostructures are predicted to exhibit novel physical properties that make them attractive candidates for the fabrication of electronic and optoelectronic devices. However, TMDCs tend to grow in the form of two-dimensional nanoplates(NPs) rather than one-dimensional nanoribbons(NRs) due to their native layered structure. Herein, we have developed a space-confined and substrate-directed chemical vapor deposition strategy for the controllable synthesis of WS2, WSe2, MoSe2, MoS2, WS2(1-x)Se2x NPs and NRs. TMDC NRs with lengths ranging from several micrometers to 100 μm have been obtained and the widths of TMDC NRs can be effectively tuned.Moreover, we found that TMDC NRs show different growth behaviors on van der Waals(vdW) and nonvd W substrates. The micro-nano structures, optical and electronic properties of synthesized TMDC NRs have been systematically investigated. This approach provides a general strategy for controllable synthesis of TMDC NRs, which makes these materials easily accessible as functional building blocks for novel optoelectronic devices.
文摘利用低能H离子对20 Me V W^(6+)预注入和未注入的钨样品进行辐照实验,考察H离子能量(20-520 e V)和辐照温度(673-1073 K)变化对钨表面微结构的影响。采用非破坏性的导电模式原子力显微镜和扫描电镜分析预注入和未注入钨样品的表面形貌和内表面缺陷分布情况。结果表明,辐照后的样品表面出现大量的纳米尺寸凸起,高能W^(6+)预注入的样品表面损伤要小于未注入的钨样品,意味着高能离子预注入会对材料的表面损伤起到抑制作用,但是当辐照温度高于1073 K时,这种抑制作用开始减弱。
文摘钼(Mo)材料被作为托卡马克装置中面向等离子体材料的候选材料被广泛研究,因此研究钼材料的辐照损伤行为对于认识聚变堆关键材料的辐照损伤机制具有重要意义。采用低能(100 e V)、大流强(约1021 ions·m-2·s-1)He+在600 oC对钼样品进行辐照实验,考察了离子辐照剂量和退火温度变化对钼材料的表面损伤作用。分别采用扫描电镜(Scanning Electron Microscope,SEM)和无损伤的导电原子力显微镜(Conductive Atomic Force Microscopy,CAFM)检测技术对辐照前后样品的微观形貌、微结构演化以及内表面缺陷分布等进行了对比研究。结果表明,He+辐照会诱导钼样品晶粒尺寸的增加,钼材料表面的晶粒取向会影响辐照缺陷的分布。这对于探索抑制材料辐照损伤的新方法具有重要的指导意义。
文摘PANI nanodots array was fabricated in AAO template with potentiostatic method in a short time.The topographic image of PANI nanodots array was characterized by scanning electron microscopy(SEM) and atomic force microscopy(AFM).The I-V characteristics of conducting PANI nanodots array was measured with conducting atomic force microscope(C-AFM) in atmosphere at room temperature.Coulomb staircase phenomena was observed in the I-V curves.
基金supported by the National Basic Research Program of China(2011CB9323012011CB808704)+2 种基金the National Natural Science Foundation of China(2112790121373236)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12020100)
文摘The kesterite-structured semiconductor Cu_2 Zn Sn(S,Se)_4(CZTSSe) is prepared by spin coating a non-hydrazine precursor and annealing at Se atmosphere. Local electrical and optoelectronic properties of the CZTSSe thin-film are explored by Kelvin probe force microscopy and conductive atomic force microscopy. Before and after irradiation, no marked potential bending and very low current flow are observed at GBs, suggesting that GBs behave as a charge recombination site and an obstacle for charge transport. Furthermore, Cd S nano-islands are synthesized via successive ionic layer adsorption and reaction(SILAR) method on the surface of CZTSSe. By comparing the work function and current flow change of CZTSSe and Cd S in dark and under illumination, we demonstrate photo-induced electrons and holes are separated at the interface of p-n junction and transferred in Cd S and CZTSSe, respectively.
