1989 Fiscal Year Final Research Report Summary
Quantum Well Effects in Ionic Insulators and Metals.
| Project/Area Number |
63460028
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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 |
固体物性
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| Research Institution | Department of pure and applied sciences, University of Tokyo. |
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Principal Investigator |
EJIRI Arisato Dept. of pure and applied sciences, Univ. of Tokyo, Assistant., 教養学部, 助手 (70012383)
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| Co-Investigator(Kenkyū-buntansha) |
NASU Takao College of Arts and Sciences. Univ. of Tokyo. Assistant Professor., 教養学部, 助教授 (60012374)
HATANO Akira Dept. of pure and applied sciences, Univ. of Tokyo, Assistant., 教養学部, 助手 (10012395)
NAKAGAWA Kazumiti Faculty of Education, Kobe University, Assistant Professor., 教育学部, 助教授 (00134403)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Alkali halide multilayer structures. / Quantum well excitons. / Confinement effect. / Interface mixture. / Interface mismatch. / Exciton in the well-layer. / Exciton in the barrier-layer. / Characterization of multilayer structure. |
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| Research Abstract |
After discovery of the quantum size effect in the KBr exciton band on the absorption spectra of alternate KCI-KBr multilayer structure in 1986, we have mainly investigated the quantum well excitons in several alkali halides and accumulated lots of knowledges on them. These knowledges are briefly explained as the follows.
The exciton band due to the well (KBr) which appears at the lowest energy on the absorption spectra of KCI-KBr or RbCl-xBr multilayer structures exhibits a blueshift in affecting with two effects, namely an increase of the exciton kinetic due to quantum confinement and an increase of band gap in the well due to interface mixture formation. Whereas the confinement of exciton wave function is effectively occurred even in the well with width wider by ten times of exciton Bohr radius and seems to make the rise of exciton band steeper appreciably.
The influence of the layer-layer interface mixture to the blueshift which is remarkable in the noannealed multilayer can be decreased by thermal annealing at appropriate temperature for layer by layer, and an interface mismatch free and interface mixture free structure is realized in annealed RbCl-KBr multilayer. The.interface mixture formation strongly depends on annealing temperature and evaporation, speed, and at the present, it is considered that the temperature 180ﾟ-200ﾟ C and the speed less than 1A^^ﾟ/sec are favorable.
It is also revealed that, if.there is a large difference of lattice constant between the layer and the substrate crystal, the interface mismatch effect is important in the case of very thin film less than 100A^^ﾟ.
The experimental chamber which is just constructed by the grant will be worked to research the conditions of the thermal annealing and the evaporation speed of thin layers in near future.
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Research Products
(16 results)
