Opto–electromechanical coupling at the nanoscale is an important topic in new scientific studies and technical applications. In this work, the optically manipulated electromechanical behaviors of individual cadmium s...Opto–electromechanical coupling at the nanoscale is an important topic in new scientific studies and technical applications. In this work, the optically manipulated electromechanical behaviors of individual cadmium sulfide(CdS) nanowires are investigated by a customer-built optical holder inside transmission electron microscope, wherein in situ electromechanical resonance took place in conjunction with photo excitation. It is found that the natural resonance frequency of the nanowire under illumination becomes considerably lower than that under darkness. This redshift effect is closely related to the wavelength of the applied light and the diameter of the nanowires. Density functional theory(DFT) calculation shows that the photoexcitation leads to the softening of CdS nanowires and thus the redshift of natural frequency, which is in agreement with the experimental results.展开更多
以微/纳型信息器件所需的能量供应技术为对象,对全球微/纳型发电技术相关专利产出进行定量分析,揭示当前专利活动特点,确定相关技术领域的重要研发方向与重点技术,并在综合分析基础上就今后发展提出了参考建议。主要分析工具包括汤森科...以微/纳型信息器件所需的能量供应技术为对象,对全球微/纳型发电技术相关专利产出进行定量分析,揭示当前专利活动特点,确定相关技术领域的重要研发方向与重点技术,并在综合分析基础上就今后发展提出了参考建议。主要分析工具包括汤森科技信息集团的数据分析工具TDA(Thomson Data Analyzer)、TI(Thomson Innovation)分析平台、中国科学院国家科学图书馆专利在线分析系统2.0。展开更多
Atomic layers of hexagonal boron nitride(h-BN)crystal are excellent candidates for structural materials as enabling ultrathin,two-dimensional(2D)nanoelectromechanical systems(NEMS)due to the outstanding mechanical pro...Atomic layers of hexagonal boron nitride(h-BN)crystal are excellent candidates for structural materials as enabling ultrathin,two-dimensional(2D)nanoelectromechanical systems(NEMS)due to the outstanding mechanical properties and very wide bandgap(5.9 eV)of h-BN.In this work,we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies(from~5 to~70 MHz),and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices.First,we demonstrate a dry-transferred doubly clamped h-BN membrane with~6.7 nm thickness,the thinnest h-BN resonator known to date.In addition,we fabricate circular drumhead h-BN resonators with thicknesses ranging from~9 to 292 nm,from which we measure up to eight resonance modes in the range of~18 to 35 MHz.Combining measurements and modeling of the rich multimode resonances,we resolve h-BN’s elastic behavior,including the transition from membrane to disk regime,with built-in tension ranging from 0.02 to 2 N m−1.The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances.The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms,including anisotropic built-in tension and bulging,thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.21773303,21872172,51472267,and 51421002)the Chinese Academy of Sciences(Grant Nos.ZDYZ2015-1,XDB30000000,and XDB07030100)
文摘Opto–electromechanical coupling at the nanoscale is an important topic in new scientific studies and technical applications. In this work, the optically manipulated electromechanical behaviors of individual cadmium sulfide(CdS) nanowires are investigated by a customer-built optical holder inside transmission electron microscope, wherein in situ electromechanical resonance took place in conjunction with photo excitation. It is found that the natural resonance frequency of the nanowire under illumination becomes considerably lower than that under darkness. This redshift effect is closely related to the wavelength of the applied light and the diameter of the nanowires. Density functional theory(DFT) calculation shows that the photoexcitation leads to the softening of CdS nanowires and thus the redshift of natural frequency, which is in agreement with the experimental results.
文摘以微/纳型信息器件所需的能量供应技术为对象,对全球微/纳型发电技术相关专利产出进行定量分析,揭示当前专利活动特点,确定相关技术领域的重要研发方向与重点技术,并在综合分析基础上就今后发展提出了参考建议。主要分析工具包括汤森科技信息集团的数据分析工具TDA(Thomson Data Analyzer)、TI(Thomson Innovation)分析平台、中国科学院国家科学图书馆专利在线分析系统2.0。
基金We are grateful for support from the National Academy of Engineering(NAE)Grainger Foundation Frontier of Engineering(FOE)Award(FOE2013-005)the National Science Foundation CAREER Award(Grant ECCS-1454570)partial support from the Department of Energy(DOE)EERE Award(Grant DE-EE0006719),a ThinkEnergy Fellowship(X.-Q.Zheng),and the Case School of Engineering.A portion of the device fabrication was performed at the Cornell NanoScale Science and Technology Facility(CNF),a member of the National Nanotechnology Infrastructure Network(NNIN)supported by the National Science Foundation(Grant ECCS-0335765).
文摘Atomic layers of hexagonal boron nitride(h-BN)crystal are excellent candidates for structural materials as enabling ultrathin,two-dimensional(2D)nanoelectromechanical systems(NEMS)due to the outstanding mechanical properties and very wide bandgap(5.9 eV)of h-BN.In this work,we report the experimental demonstration of h-BN 2D nanomechanical resonators vibrating at high and very high frequencies(from~5 to~70 MHz),and investigations of the elastic properties of h-BN by measuring the multimode resonant behavior of these devices.First,we demonstrate a dry-transferred doubly clamped h-BN membrane with~6.7 nm thickness,the thinnest h-BN resonator known to date.In addition,we fabricate circular drumhead h-BN resonators with thicknesses ranging from~9 to 292 nm,from which we measure up to eight resonance modes in the range of~18 to 35 MHz.Combining measurements and modeling of the rich multimode resonances,we resolve h-BN’s elastic behavior,including the transition from membrane to disk regime,with built-in tension ranging from 0.02 to 2 N m−1.The Young’s modulus of h-BN is determined to be EY≈392 GPa from the measured resonances.The ultrasensitive measurements further reveal subtle structural characteristics and mechanical properties of the suspended h-BN diaphragms,including anisotropic built-in tension and bulging,thus suggesting guidelines on how these effects can be exploited for engineering multimode resonant functions in 2D NEMS transducers.
