| Project/Area Number |
11440100
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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 | Riken |
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Principal Investigator |
SUZUKI Takanori Riken, Senior Reswrcher, 表面界面工学研究室, 副主任研究員 (60124369)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 2001: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1999: ¥3,600,000 (Direct Cost: ¥3,600,000)
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| Keywords | semiconductor surfaces / silicon / Surface SHG / surface electric field / surface charge layer / laser / carrier excitation / local electric field / キャリア励起 |
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| Research Abstract |
Local electric fields on the clean semiconductor surface is evaluated by means of second-harmonic generation technique. The changes in the band-bending induced by carrier excitation by an intense pulsed laser has manifested as a change in the generated SHG intensity througil the third order nonlinear optical susceptibility which is electric-field dependent. However, it is found that the sample temperature increase can also contribute to the change in the SHG intensity through the temperature dependent SHG clarified in our work. Thus, the observed dependence of the SH intensity on the pump fluence was analysed by taking into accont the both effects.
In another attempt to evaluate the surface local electric field, the seeond-harmonic generation SHG from silicon nanocrystallites in polycrystalline films prepared by low-temperature plasma-enhanced chemical-vapor deposition has been studied. An increase in the SHG signal by decrease in the sizes of crystallites is, interpreted by the increased local electric filed. We also studied SHG during the adsorption of silver at room temperature as well as the formation of the Si(111)-【square root】3x【square root】 : 3-Ag surface at elevated temperatures on Si(111)-7x7.The SHG intensity is found to depend on the density of the two-dimensional adatom gas (2DAG) on the Si(111)-【square root】3x【square root】3-Ag surface as a function of temperature and silver flux. The increase of SHG with silver coverage at room temperature is interpreted by a surface plasmon resonance, while that at elevated temperatures show the role of 3D islands formed beside the Si(111)-【square root】3x【square root】 : 3-Ag.
Local electron spins on the Si(111)-7x7 surface are also evidenced by our SHG detection method.
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