1989 Fiscal Year Final Research Report Summary
In Situ Scanning Tunneling Microscopy for Analysis of Surface
| Project/Area Number |
63850160
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
工業分析化学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
ITAYA Kingo Tohoku Univ., Faculty of Eng., Assit. Prof., 工学部, 助教授 (40125498)
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| Co-Investigator(Kenkyū-buntansha) |
TOMITA Eisuke Seiko Instrument Inc., Res. &Dev. Dept, 研究開発部, 主任
ATAKA Tatsuaki Seiko Instrument Inc., Res. &Dev. Dept, 研究開発部, 課長
SUGAWARA Shizuo Tohoku Univ., Faculty of Eng., Assist., 工学部, 助手 (30196703)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Scanning tunneling microscope(STM) / Electrochemistry / In situ observation / Electrodeposition / Dissolution / Single crystal metal electrode |
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| Research Abstract |
We have constructed a scanning tunneling microscope(STM) for operation in electrochemical conditions in electrolyte solutions. The electrochemical potentials of the tunneling tip and the substrate with respect to a reference electrode can be simultaneously controlled. The apparatus offers a new possibility for complete. in situ observation of electrode surfaces in electrolyte solutions under potentiostatic conditions. The electrochemical deposition and dissolution of Ag have been investigated with this instrument.
In situ STM was applied to single-crystal platinum(111) surfaces both before and after electrochemical potential cycling in an aqueous sulfuric acid solution. Steps observed on a Pt(111)facet were usually located on nearly parallel straight lines or on the directions forming an angle of close to 60ﾟ, as expected for a surface with threefold symmetry. The height of each step was in accord with the monatomic step height of 0.238nm on the Pt(111) surface. Randomly oriented islands a few atoms in height were clearly observed on the terraces after five potential cyclings. It was suggested that Pt adatoms produced by the reduction of the oxide are coagulated on the terraces.
The topography and the surface electronic structure of various semiconductor electrodes have been examined in aqueous solutions by means of STM. It is shown, for example, that hydrogen-terminated Si surface are resistant to oxidation even in aqueous solutions. The tunneling current-electrode potential(I- E)curve suggests the existence of surface states. STM images of photoelectrochemically oxidized surfaces have been obtained.
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