1997 Fiscal Year Final Research Report Summary
Local spectroscopy by spectrally resolved photon mapping of STM induced luminescnce from nanometer-size particles
| Project/Area Number |
08454082
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
NISHITANI Ryusuke Kyushu Institute of Technology, Department of Computer Science and Electronics, Associate Professor, 情報工学部, 助教授 (50167566)
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| Project Period (FY) |
1996 – 1997
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| Keywords | STM / photon emission / scanning tunneling microscope / local electronic structure / fine particle / surface plasmon / nanoscale / liquid-solid interface |
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| Research Abstract |
1. We have carried out the spectral mapping measurements of tunneling induced luminescence in scanning tunneling microscopy(STM) of nanoscale gold metal particles on the graphite surface. The luminescence spectra are recorded simultaneously with the measurement of STM topography image by using an intensified CCD detector and a spectrograph. Based on the measurements, spectrally resolved photon intensity images are obtained for various spectral bands. Those photon intensity images are compared with the topography image. We have observed two types of spectrally dependent photon images. One is associated with a shorter wavelength (-650 nm) mode and the other a longer wavelength (-700 nm) mode. The photon map of shorter wavelength (-650 nm) is correlated with grain morphology.
2. We have observed STM-induced photon emission at liquid-solid interface. The measurement of STM induced luminescence are made in non-aqueous liquid which has a wide potential window. The luminescence can be recorded only for 1-4 dioxane at the STM bias voltage at 4.5 V while various liquid has been tried. The result shows that the spectrum obtained in the liquid is shifted toward longer wavelength compared with that in UHV and air. This result suggests that the shift is caused by the existence of a dielectric medium in the tunneling gap, and that the increase in dielectric constant of a medium between tip and sample causes a red shift of the emission spectra. We have calculated the spectra of the STM-induced photon emission as a parameter of dielectric constant of dielectric media in the tunneling gap of STM.The calculation shows that the peak of the emission spectrum shifts to a longer
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