| Project/Area Number |
10450018
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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 |
表面界面物性
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| Research Institution | Osaka University |
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Principal Investigator |
MORITA Seizo Department of Electronic Engineering, Graduate School of Engineering, Osaka University Professor, 大学院・工学研究科, 教授 (50091757)
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| Co-Investigator(Kenkyū-buntansha) |
SUGAWARA Yasuhiro Department of Electronic Engineering, Graduate School of Engineering, Osaka University Associate Professor, 大学院・工学研究科, 助教授 (40206404)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥12,300,000 (Direct Cost: ¥12,300,000)
Fiscal Year 1999: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1998: ¥9,400,000 (Direct Cost: ¥9,400,000)
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| Keywords | atomic force microscope / atomic force / electrostatic force microscope / electrostactic force / well-defined surface / atomic resolution / semiconductor surface / charge |
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| Research Abstract |
The electrostatic force microscope (EFM) offers new opportunity to measure a variety of electrostatic properties on the surface on a sub-micron scale, which result from nonuniform charge distribution and variations in surface work function. For example, potentiometry, imaging of contact-electrified charge and its dissipation process on insulating surfaces and so on have been demonstrated. Unfortunately, so far, the lateral resolution of the EFM has been insufficient. This is due to the following two main reasons : (i) It is rather difficult to measure weak distance dependence of the electrostatic force with a good signal-to-noise (S/N) ratio. (ii) It is much difficult to separate the electrostatic force from the van der Waals force.
In this project, we demonstrated a novel method to detect the van der Waals and the electrostatic force interactions simultaneously, which was based on the Frequency modulation (FM) detection method in UHV. For the first time, the surface structure and the surface charge at atomic-scale point defects on the GaAs (110) surface were clearly resolved with true atomic resolution. The contrast of the electrostatic force image at a point defect showed monotonous change in the positive sample bias region, while it complicatedly changed in the negative sample bias region. From this bias voltage dependence, we could verify that the sign of the atomically resolved surface charge at the point defect was positive. Furthermore, we investigated the measurement condition of the atomic resolution imaging of the charge using the EFM.
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