Exploring of New Properties of Non-Epitaxial Metallic Superlattices and Development of High Conductivity Superlattice Films
| Project/Area Number |
59460050
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Faculty of Technology, Gunma University |
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Principal Investigator |
TANUMA Sei-ichi Faculty of Technology, Gunma University (Professor), 工学部, 教授 (70013448)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Kazuo Faculty of Technology, Gunma University (Research Associate), 工学部, 助手 (30106900)
SASAKI Yoshisato Faculty of Technology, Gunma University (Associate Professor), 工学部, 助教授 (30008445)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥8,100,000 (Direct Cost: ¥8,100,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1984: ¥6,400,000 (Direct Cost: ¥6,400,000)
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| Keywords | superlattice film / ultra-high vacuum / epitaxial deposition / non-epitaxy / metallic superlattice / molecular beam evaporation / 半金属 / 微少ギャップ半導体 / アンダーソン局在 |
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| Research Abstract |
1.Metallic superlattice films of Ag-Bi, Ag-Au, Yb-Sb and Bi-Sb systems were grown in order to investigate electrical properties and explore new features. In a possible stage of work, non-epitaxial film growth was done. By X-ray diffraction, superlattice structure was confirmed. For Ag-Bi and Ag-Au films, resistivity <rho> was proportional to 1/ <lambda> where <lambda> was the layer period.
2.Yb-Sb superlattice system was investigated due to an expectation of getting some new electrical property. By setting the layer number ratio 1:1, the period of thickness <lambda> was varied from 10 to 1000 <ang> and the resistivities were measured as the function of temperature. The films of <lambda> <>!-> 100 <ang> , metallic behavior was obtained, while the films of <lambda> <100 <ang> ,semiconductive negative temperature dependence was found. The log <rho> vs. 1/T was not strait, but log <rho> vs. 1/( <T^(1/4)> gave a good fit of straight line which fact meant the system behaved as the Anderson lo
… More
calized state. Thus the Yb-Sb superlattice system has been found to show metal・non-metal transition very sharply at the period of <lambda> <:!=> 100 <ang> .
3.Bi-Sb superlattice system was investigated rather in detail. The bulk Bi-Sb system is known as a whole range solid solution, nevertheless, 4 to 40 atom.% Sb alloy shows semiconducting nature. How is the behavior for the metallic superlattice films? The alloying concentration of Sb was substituted by the layer number ratio of Sb to the total perioic layer number. On the specimens of about ten kinds of Sb layer ratios, resistivity, Hall coefficient and magnetoresistance were measured as functions of temperature from 300K to 77K. Furthermore, the resistivity was measured as the function of temperature and negative temperature gradients were obtained for 0 to 48 Sb ratio, which gave apparent energy gap values. By analysing these data, such conclusion has been obtained that 4 to 48 Sb ratio of this superlattice system shows semiconductive nature and the maximum energy gap is 13 meV. It may be reasonable because the estimated de Broglie wave lengths of the carriers are 650 <ang> for Bi and 170 <゜!A> for Sb which are generally longer than the periodic length. Less
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Report
(1 results)
Research Products
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