The grain size and surface morphology of sputtered Au films are studied by x-ray diffraction and atomic force microscope. For as-deposited samples the grain growth mechanism is consistent with the two-dimensional （2D...The grain size and surface morphology of sputtered Au films are studied by x-ray diffraction and atomic force microscope. For as-deposited samples the grain growth mechanism is consistent with the two-dimensional （2D） theory, which gives relatively low diffusion coefficient during deposition. Annealing process demonstrates the secondary grain growth mechanism in which the thickness dependence of grain boundary energy plays a key role. The surface roughness increases with the increase of grain size.展开更多
Gold nanoparticles dispersed Y2O3 films were prepared through a sol-gel method by using yttrium acetate and Au nanoparticles colloid as precursors. The films were characterized by X-ray diffraction （XRD）, transmissi...Gold nanoparticles dispersed Y2O3 films were prepared through a sol-gel method by using yttrium acetate and Au nanoparticles colloid as precursors. The films were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and UV-VIS absorption spectra. XRD patterns and TEM images of Y2O3 ＋ Au films give the same resuits on structure and particle size as that of pure Y2O3 films. The surface plasma resonance （SPR） of Au nanoparticles in Y2O3 ＋ Au film was observed around 550 nm in the absorption spectrum and its position shifts to red with increasing annealing temperature is caused by the increase of dielectric constant of Y2O3 matrix and the size of Au nanoparticles. The second and third order nonlinear optical effects of Y2O3 ＋ Au films were also observed. The photoluminescent properties of Y2O3 ： Eu ＋ Au films were investigated and results indicate that there exist an energy transfer from Eu^3 ＋ to Au nanoparticles and this energy transfer decreases the emission of Eu^3 ＋ in Y2O3 ： Eu ＋ Au film.展开更多
The magnetic impurity scattering plays an important role in the phase coherence behavior of thin films.By using the thickness and disorder dependences of the low temperature logarithmic anomaly in resistivity we are a...The magnetic impurity scattering plays an important role in the phase coherence behavior of thin films.By using the thickness and disorder dependences of the low temperature logarithmic anomaly in resistivity we are able to determine the concentration of magnetic impurities in Au films and demonstrate that the low temperature saturation or plateau in phase decoherence time is closely related with the Kondo effect.展开更多
Ablation process of 1-kHz femtosecond lasers （pulse duration of 148 fs, wavelength of 775 nm） of Au film on silica substrates is studied. The thresholds for single and multi pulses can be obtained directly from the ...Ablation process of 1-kHz femtosecond lasers （pulse duration of 148 fs, wavelength of 775 nm） of Au film on silica substrates is studied. The thresholds for single and multi pulses can be obtained directly from the relation between the squared diameter D^2 of the ablated craters and the laser fluence Ф0. From the plot of the accumulated laser fluence NCth（N） and the number of laser pulses N, incubation coefficient of Au film is obtained to be 0.765. Some experimental data obtained around the single pulse threshold are in good agreement with the theoretical calculation.展开更多
Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal an...Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.展开更多
Free-standing two-dimensional(FS-2D) materials of covalent or ionic bonds can be prepared through mechanical exfoliation by virtue of their intrinsic layered crystal structures.Here,following this strategy,it was repo...Free-standing two-dimensional(FS-2D) materials of covalent or ionic bonds can be prepared through mechanical exfoliation by virtue of their intrinsic layered crystal structures.Here,following this strategy,it was reported the fabrication of large-area FS-2D Au films with controllable lattice orientations via an electrochemical hydrogen-detaching method.It was further characterized the catalytic properties of FS-2D Au.The(111)-oriented FS-2D Au with 20 nm in thickness shows a catalytic conversion up to 43.8% for the oxidation of cyclohexane as a model reaction system,a result of more than double of generally reported values.The exceptionally high catalytic activity could be attributed to the flexible structure of the FS-2D Au catalyst,which differs from the rigid structure of general catalysts.The results give useful implications for large-scale productions of a variety of FS-2D metals with controllable orientations,by which their applications may not be confined to catalysis chemistry.展开更多
Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma s...Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.展开更多
Sputter-deposited Au/NisoFeso bilayer films were annealed in a vacuum of 5×10^-4 Pa at 523 to 723 K for 30 or 90 min. The characteristics of the bilayer films were determined by Auger electron spectroscopy, field...Sputter-deposited Au/NisoFeso bilayer films were annealed in a vacuum of 5×10^-4 Pa at 523 to 723 K for 30 or 90 min. The characteristics of the bilayer films were determined by Auger electron spectroscopy, field emission scanning electron microscopy, X- ray diffractometry, a four-point probe technique, and an alternating gradient magnetometer. When the annealing temperature and time reached 723 K and 90 min, Ni and Fe atoms markedly diffused into the Au layer. The grain size of the Au layer did not change markedly with the annealing condition. As the annealing time was 30 min and the annealing temperature exceeded 573 K, the resistance of the bilayer film increased with increasing the annealing temperature. Furthermore, the resistance of the bilayer film annealed at 723 K for 90 ,nin was lower than that of the bilayer film annealed at 723 K for 30 min. All the bilayer films showed magnetic hysteresis loops. The as-deposited bilayer film showed a hard magnetization. The bilayer film represented an easy magnetization with increasing the annealing temperature. The Au/Ni50Fe50 film that annealed at 723 K for 90 min had the lowest saturation magnetization.展开更多
This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-la...This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized Z-scans in femtosecond time scale. The nonlinear absorption coefficient βeff of single-layer Au-TiO2 films is measured to be -2.3×10^3-0.76×10^3 cm/GW with Au atom content 15%-66%. The βeff value of the 10-layer Au-TiO2 graded film is enhanced to be -2.1×10^4cm/GW calculated from p-polarized Z-scans, which is about ten times the maximum βeff of single-layer films. Broadened response in the wavelength region 730-860 nm of the enhanced optical nonlinearity of graded Au-TiO2 composite films was also investigated.展开更多
We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green＇s function theory. In the process of...We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green＇s function theory. In the process of replacing the P atoms with Si atoms every other line from the middle of monolayer blue phosphorus molecular structure, the substitution of Si atoms changes the properties of Au-P-Au molecular junction significantly. Interestingly, the current value has a symmetric change as a parabolic curve with the peak appearing in Au-Si_1P_1-Au molecular junction, which provides the most stable current of 15.00 nA in a wide voltage range of 0.70-2.70 V.Moreover, the current-voltage characteristics of the structures indicate that the steps tend to disappear revealing the property similar to metal when the Si atoms dominate the molecular junction.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2006CB91304)the Knowledge Innovation Program of the Chinese Academy of Sciences
文摘The grain size and surface morphology of sputtered Au films are studied by x-ray diffraction and atomic force microscope. For as-deposited samples the grain growth mechanism is consistent with the two-dimensional （2D） theory, which gives relatively low diffusion coefficient during deposition. Annealing process demonstrates the secondary grain growth mechanism in which the thickness dependence of grain boundary energy plays a key role. The surface roughness increases with the increase of grain size.
文摘Gold nanoparticles dispersed Y2O3 films were prepared through a sol-gel method by using yttrium acetate and Au nanoparticles colloid as precursors. The films were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and UV-VIS absorption spectra. XRD patterns and TEM images of Y2O3 ＋ Au films give the same resuits on structure and particle size as that of pure Y2O3 films. The surface plasma resonance （SPR） of Au nanoparticles in Y2O3 ＋ Au film was observed around 550 nm in the absorption spectrum and its position shifts to red with increasing annealing temperature is caused by the increase of dielectric constant of Y2O3 matrix and the size of Au nanoparticles. The second and third order nonlinear optical effects of Y2O3 ＋ Au films were also observed. The photoluminescent properties of Y2O3 ： Eu ＋ Au films were investigated and results indicate that there exist an energy transfer from Eu^3 ＋ to Au nanoparticles and this energy transfer decreases the emission of Eu^3 ＋ in Y2O3 ： Eu ＋ Au film.
基金supported by the National Basic Research Program of China (Grant No. 2006CB91304)the Knowledge Innovation Project of Chinese Academy of Sciences
文摘The magnetic impurity scattering plays an important role in the phase coherence behavior of thin films.By using the thickness and disorder dependences of the low temperature logarithmic anomaly in resistivity we are able to determine the concentration of magnetic impurities in Au films and demonstrate that the low temperature saturation or plateau in phase decoherence time is closely related with the Kondo effect.
基金This work was supported by the Key Grant Project of the Ministry of Education of China (No. 10410)the Science and Technology Development Project Fund of Tianjin (No. 043103911)the Specialized Research Fund for the Doctoral Program of Higher Education (No.2003056021), and the Postdoctoral Science Foundation in China.
文摘Ablation process of 1-kHz femtosecond lasers （pulse duration of 148 fs, wavelength of 775 nm） of Au film on silica substrates is studied. The thresholds for single and multi pulses can be obtained directly from the relation between the squared diameter D^2 of the ablated craters and the laser fluence Ф0. From the plot of the accumulated laser fluence NCth（N） and the number of laser pulses N, incubation coefficient of Au film is obtained to be 0.765. Some experimental data obtained around the single pulse threshold are in good agreement with the theoretical calculation.
基金supported by the National Natural Science Foundation of China(Grant No.11274082)the Shandong Excellent Young Scientist Research Award Fund Project,China(Grant No.BS2011CL002)
文摘Highly ordered TiO2 nanotube array （TNA） films are fabricated by using an anodic oxidation method. Au nanoparticles （NPs） films are decorated onto the top of TNA films with the aid of ion-sputtering and thermal annealing. An enhanced photocatalytic activity under ultraviolet C （UVC, 266 nm） light irradiation is obtained compared with that of the pristine TNA, which is shown by the steady-state photoluminescence （PL） spectra. Furthermore, a distinct blue shift in the nanosecond time-resolved transient photoluminescence （NTRT-PL） spectra is observed. Such a phenomenon could be well explained by considering the competition between the surface photocatalytic process and the recombination of the photo-generated carriers. The enhanced UV photocatalytic activities of the Au-TNA composite are evaluated through photo-degradation of methyl orange （MO） in an aqueous solution with ultraviolet-visible absorption spectrometry. Our current work may provide a simple strategy to synthesize defect-related composite photocatalytic devices.
基金financially supported by the Fundamental Research Funds for the Central Universities (No.FRFSD-12-027A)the New Century Excellent Talents in Universities (No.NCET-12-0778)+2 种基金Innovation on Working Methodology of Ministry of Science and Technology of China (No.2012IM030500)the National Natural Science Foundation of China (No.51328202)China Scholarship Council (No.201308110345)
文摘Free-standing two-dimensional(FS-2D) materials of covalent or ionic bonds can be prepared through mechanical exfoliation by virtue of their intrinsic layered crystal structures.Here,following this strategy,it was reported the fabrication of large-area FS-2D Au films with controllable lattice orientations via an electrochemical hydrogen-detaching method.It was further characterized the catalytic properties of FS-2D Au.The(111)-oriented FS-2D Au with 20 nm in thickness shows a catalytic conversion up to 43.8% for the oxidation of cyclohexane as a model reaction system,a result of more than double of generally reported values.The exceptionally high catalytic activity could be attributed to the flexible structure of the FS-2D Au catalyst,which differs from the rigid structure of general catalysts.The results give useful implications for large-scale productions of a variety of FS-2D metals with controllable orientations,by which their applications may not be confined to catalysis chemistry.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 50842028 and 50972012)the National Basic Research Program of China (Grant No 2007CB613301)
文摘Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications. Au/SiO2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering. Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO2 matrix. Optical absorption peaks due to the surface plasmon resonance of Au particles are observed. The absorption property is enhanced with the increase of Au content, showing a maximum value in the films with 37 vol% Au. The absorption curves of the Au/SiO2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory. Increasing Au content over 37 vol% results in the partial connection of Au particles, whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk. The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases.
文摘Sputter-deposited Au/NisoFeso bilayer films were annealed in a vacuum of 5×10^-4 Pa at 523 to 723 K for 30 or 90 min. The characteristics of the bilayer films were determined by Auger electron spectroscopy, field emission scanning electron microscopy, X- ray diffractometry, a four-point probe technique, and an alternating gradient magnetometer. When the annealing temperature and time reached 723 K and 90 min, Ni and Fe atoms markedly diffused into the Au layer. The grain size of the Au layer did not change markedly with the annealing condition. As the annealing time was 30 min and the annealing temperature exceeded 573 K, the resistance of the bilayer film increased with increasing the annealing temperature. Furthermore, the resistance of the bilayer film annealed at 723 K for 90 ,nin was lower than that of the bilayer film annealed at 723 K for 30 min. All the bilayer films showed magnetic hysteresis loops. The as-deposited bilayer film showed a hard magnetization. The bilayer film represented an easy magnetization with increasing the annealing temperature. The Au/Ni50Fe50 film that annealed at 723 K for 90 min had the lowest saturation magnetization.
基金Project supported by the National Natural Science Foundation of China (Grant No 10474075)
文摘This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized Z-scans in femtosecond time scale. The nonlinear absorption coefficient βeff of single-layer Au-TiO2 films is measured to be -2.3×10^3-0.76×10^3 cm/GW with Au atom content 15%-66%. The βeff value of the 10-layer Au-TiO2 graded film is enhanced to be -2.1×10^4cm/GW calculated from p-polarized Z-scans, which is about ten times the maximum βeff of single-layer films. Broadened response in the wavelength region 730-860 nm of the enhanced optical nonlinearity of graded Au-TiO2 composite films was also investigated.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374033,11774030,51735001 and 61775016the Fundamental Research Funds for the Central Universities under Grant No 2017CX10007
文摘We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green＇s function theory. In the process of replacing the P atoms with Si atoms every other line from the middle of monolayer blue phosphorus molecular structure, the substitution of Si atoms changes the properties of Au-P-Au molecular junction significantly. Interestingly, the current value has a symmetric change as a parabolic curve with the peak appearing in Au-Si_1P_1-Au molecular junction, which provides the most stable current of 15.00 nA in a wide voltage range of 0.70-2.70 V.Moreover, the current-voltage characteristics of the structures indicate that the steps tend to disappear revealing the property similar to metal when the Si atoms dominate the molecular junction.
