1995 Fiscal Year Final Research Report Summary
Development of a Light Detection System Combined with a Transmission Electron Microscope
| Project/Area Number |
06555004
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials science/Crystal engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
YAMAMOTO Naoki Tokyo Institute of Technology, Phys.Dept., Associate Professor, 理学部, 助教授 (90108184)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMIZU Takehiko ATAGO BUSSAN Co.Ltd, System Development Devision, the Chief of the Devision, システム開発部, 課長
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| Project Period (FY) |
1994 – 1995
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| Keywords | Electron Microscope / Cherenkov Radiation / Transition Radiation / Cathodoluminescence / Thin Films |
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| Research Abstract |
The purpose of this research is to develop a light detection system combined with a transmission electon microscope which has a capability of converged electron beam of a nanometer size. A spectrum of light emitted from a localized region can be obtained by using a monochrometer, a photomultiplier tube and a photon counter and is displayd by a mini-computer. The computer also controls the electron beam through a TEM scanning system and a monochromatic photon image can be obtained in a monitor. The spatial resolution of the photon image is less than 0.1mum.
This system has been applied to the two subjects ; the study of Cherenkov and transition radiation from thin films, and that of cathodoluminescence. The main results are as follows.
1) Cherenkov and transition radiation : Emission from a mica film is contributed mainly from Cherenkov radiation in the forward direction, while transition radiation is also considerable in the backward direction, which gives set of peaks in a spectrum due
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to intereference effect. Transition radiation is dominant in emissions from semiconductor and metal films. In the case of a semiconductor film some peaks correspond to maximum of the dielectric function, i.e., the interband transition.The backward emission spectrum from a thin silver filn involves a characteristic peak due to a radiative surface plasmon mode (Ferrell mode). The monochromatic photon images reveal the relation between the characteristic peaks and structural features such as lattice defects and surface morphology.
2) Cathodoluminescence of ZnS MBE grown films on GaAs substrates : The luminescence peaks associated with bound excitons and the conduction-acceptor transition were observed to appear in the CL spectra, and the correlation between spatial distribution of the luminescences and lattice deffects such as stucking fault were studied.
3) Cathodoluminescence of porous silicon : A broad luminescence peak around a wavelength of 420 nm was observed to appear together with a red emission peak. CL images of a cross-sectional sample revealed different spatial distributions of those CL emission regions. It was found from the annealing experiment and the IR absorption measurment that the 420 nm peak is related to Si-H compounds formed on the Si surface. Less
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