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Hansjoachim Freund - One of the best experts on this subject based on the ideXlab platform.

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recov...

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recovered even after silver evaporation at high temperature. Small discrepancies are explained with changes in the ZnO defect landscape, e.g., due to silver incorporation. Our experiments demonstrate how energy-transfer processes can be investigated in well-defined metal/oxide systems by means of STM-based spectroscopic techniques.

Niklas Nilius - One of the best experts on this subject based on the ideXlab platform.

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recov...

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recovered even after silver evaporation at high temperature. Small discrepancies are explained with changes in the ZnO defect landscape, e.g., due to silver incorporation. Our experiments demonstrate how energy-transfer processes can be investigated in well-defined metal/oxide systems by means of STM-based spectroscopic techniques.

Fernando Stavale - One of the best experts on this subject based on the ideXlab platform.

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recov...

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recovered even after silver evaporation at high temperature. Small discrepancies are explained with changes in the ZnO defect landscape, e.g., due to silver incorporation. Our experiments demonstrate how energy-transfer processes can be investigated in well-defined metal/oxide systems by means of STM-based spectroscopic techniques.

Leandro Pascua - One of the best experts on this subject based on the ideXlab platform.

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recov...

  • ag zno hybrid systems studied with scanning tunnelling microscopy based luminescence spectroscopy
    2016
    Co-Authors: Leandro Pascua, Fernando Stavale, Niklas Nilius, Hansjoachim Freund
    Abstract:

    Coupled metal/oxide systems are prepared by depositing and embedding Ag nanoparticles into crystalline ZnO films grown on Au(111) supports. The morphology and optical properties of the compounds are investigated by topographic imaging and luminescence spectroscopy performed in a scanning tunnelling microscope (STM). The luminescence of bare ZnO is governed by the band-recombination and a Zn-vacancy related peak. After Ag deposition, two additional maxima are detected that are assigned to the in-Plane and out-of-Plane plasmon in Ag nanoparticles and have energies below and slightly above the oxide band-gap, respectively. Upon coating the particles with additional ZnO, the out-of-Plane plasmon redshifts and loses intensity, indicating strong coupling to the oxide electronic system, while the in-Plane Mode broadens but remains detectable. The original situation can be restored by gently heating the sample, which drives the silver back to the surface. However, the optical response of pristine ZnO is not recovered even after silver evaporation at high temperature. Small discrepancies are explained with changes in the ZnO defect landscape, e.g., due to silver incorporation. Our experiments demonstrate how energy-transfer processes can be investigated in well-defined metal/oxide systems by means of STM-based spectroscopic techniques.

Kohei Imura - One of the best experts on this subject based on the ideXlab platform.

  • characterization of overlapped plasmon Modes in a gold hexagonal plate revealed by three dimensional near field optical microscopy
    2019
    Co-Authors: Takuya Matsuura, Keisuke Imaeda, Seiju Hasegawa, Hiromasa Suzuki, Kohei Imura
    Abstract:

    A detailed characterization of plasmon Modes is important not only for a deeper understanding of plasmons but also for their practical applications. In this study, we investigated the three-dimensional near-field characteristics of high-order plasmon Modes excited in a gold hexagonal nanoplate. From the near-field spectroscopic images, we found that both in-Plane and out-of-Plane plasmon Modes observed near 900 nm were spectrally and spatially overlapped. We performed three-dimensional near-field measurement to reveal the optical characteristics of the overlapped Modes in detail. We found that the steric near-field distribution near the nanoplate strongly depended on the plasmon Mode, and the out-of-Plane Mode confines electromagnetic fields more tightly than the in-Plane Mode. We also found that the in-Plane Mode was dominantly visualized as the probe tip–sample distance increased. These findings demonstrate that the three-dimensional near-field technique enables selective visualization of a single plasm...

  • Characterization of Overlapped Plasmon Modes in a Gold Hexagonal Plate Revealed by Three-Dimensional Near-Field Optical Microscopy
    2019
    Co-Authors: Takuya Matsuura, Keisuke Imaeda, Seiju Hasegawa, Hiromasa Suzuki, Kohei Imura
    Abstract:

    A detailed characterization of plasmon Modes is important not only for a deeper understanding of plasmons but also for their practical applications. In this study, we investigated the three-dimensional near-field characteristics of high-order plasmon Modes excited in a gold hexagonal nanoplate. From the near-field spectroscopic images, we found that both in-Plane and out-of-Plane plasmon Modes observed near 900 nm were spectrally and spatially overlapped. We performed three-dimensional near-field measurement to reveal the optical characteristics of the overlapped Modes in detail. We found that the steric near-field distribution near the nanoplate strongly depended on the plasmon Mode, and the out-of-Plane Mode confines electromagnetic fields more tightly than the in-Plane Mode. We also found that the in-Plane Mode was dominantly visualized as the probe tip–sample distance increased. These findings demonstrate that the three-dimensional near-field technique enables selective visualization of a single plasmon Mode even if multiple Modes are spatially and spectrally overlapped

  • Static and Dynamic Near-Field Measurements of High-Order Plasmon Modes Induced in a Gold Triangular Nanoplate
    2018
    Co-Authors: Keisuke Imaeda, Seiju Hasegawa, Kohei Imura
    Abstract:

    Precise understanding of the spatiotemporal characteristics of plasmons is essential for the development of applications of plasmonic nanoparticles. In this study, we investigated the spatiotemporal properties of high-order plasmon Modes induced in a gold triangular nanoplate by static and dynamic near-field measurements. The near-field transmission measurements revealed that in-Plane and out-of-Plane polarized plasmon Modes were simultaneously excited and these Modes spectroscopically and spatially overlapped. The superposition of these Modes was visualized in the near-field two-photon excitation image of the nanoplate. We performed time-resolved autocorrelation measurements on the nanoplate and found that the correlation width was broader than the excitation pulse due to the plasmon dephasing process. From the correlation width map of the nanoplate, we experimentally demonstrated that the out-of-Plane plasmon Mode exhibits a longer dephasing time than the in-Plane plasmon Mode. These findings indicate that the out-of-Plane Mode is desirable for improving the performance of plasmons in various applications