2007 Fiscal Year Final Research Report Summary
Multi-quantum-well polaritons in semiconductor nanocolumns
| Project/Area Number |
18340092
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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 |
Condensed matter physics I
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| Research Institution | Sophia University |
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Principal Investigator |
EMA Kazuhiro Sophia University, Physics, Professor (40194021)
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| Co-Investigator(Kenkyū-buntansha) |
KUNUGITA Hideyuki Sophia university, Physics, Assistant Professor (50296886)
OHTSUKI Tomi Sophia university, Physics, Professor (50201976)
KIKUCHI Akihiko Sophia university, Physics, Lecturer (90266073)
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| Project Period (FY) |
2006 – 2007
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| Keywords | semiconductor / nanocolumn / GaN / exciton / polariton / quantum well / InGaN / biexciton |
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| Research Abstract |
The purpose of this project was to observe multi-quantum-well polariton coupling in GaN and InGaN/GaN nanocolumns. However we have not observed the polariton coupling, because quantum wells in the nanocolumns have different resonance energies. We have observed peculiar optical properties due to the nanocolumn morphology. We have studied specific optical properties of the GaN nanocolumn, focusing on the influence of the columnar shape.
In photoluminescence (PL) spectrum of GaN nanocolumns with large diameters (〜100nm) there are two peaks attributed to free A-excitons (A) and bound excitons (I). With decreasing the diameter, higher-energy peaks whose energy positions correspond to B-excitons (B) and C-excitons (C) appear. In order to elucidate the origin of this, we calculated PL spectra of GaN nanocolumns considering the polaritonic effect of the excitons; i.e. considering propagation and radiation from both the top and the side surfaces of the nanocolumns. The results show that the peaks of B and C excitons become remarkable with decreasing the diameter because PL from the side surface becomes important.
We also observed biexciton emissions in GaN nanocolumns with large diameters, and found that the biexciton binding energies are higher than that in bulk samples. Although the mechanism for the increase in the binding energy is not clear at the present, we suppose that it arises from spatial confinement effect due to the nanocolumn morphology.
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Research Products
(12 results)
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[Journal Article] Photoluminescence of exciton and biexciton in GaN nanocolumns2008
Author(s)
K., Kouyama, M., Inoue, Y., Inose, N., Suzuki, H., Sekiguchi, H., Kunugita, K., Ema, A., Kikuchi, K., Kishino
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Journal Title
J. Lumi 128
Pages: 969-971
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Ultrafast intersubband relaxation dynamics at 1.55μm in GaN/AIN multiple quantum disk nanocolumns2008
Author(s)
K., Tanaka, K., Ikuno, Y., Kasai, K., Fukunaga, H., Kunugita, K., Ema, A., Kikuchi, K., Kishino
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Journal Title
J. Lumi 128
Pages: 1084-1086
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Photoluminescence of exciton and biexciton in GaN nanocolumns2007
Author(s)
K., Kouyama, M., Inoue, Y., Inose, N., Suzuki, H., Sekiguchi, H., Kunugita, K., Ema, A., Kikuchi, K., Kishino
Organizer
International Conference on Dynamical Processes in Excited States of Solids(DPC 07), Segovia
Place of Presentation
Spain
Year and Date
20070618-22
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Ultrafast intersubband relaxation dynamics at 1.55μm in GaN/A1N multiple quantum disk nanocolumns2007
Author(s)
K., Tanaka, K., Ikuno, Y., Kasai, K., Fukunaga, H., Kunugita, K., Ema, A., Kikuchi, K., Kishino
Organizer
International Conference on Dynamical Processes in Excited States of Solids(DPC 07), Segovia
Place of Presentation
Spain
Year and Date
20070618-22
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Ultrafast intersubband relaxation dynamics and coherent nonlinearity in bulk and waveguide structures of GaN/A1N multiple quantum wells2006
Author(s)
K., Ikuno, J., Hamazaki, K., Tanaka, H., Kunugita, K., Ema, A., Kikuchi, K., Kishino
Organizer
28th International Conference on the Physics of Semiconductors(ICPS'06)
Place of Presentation
Vienna, Austria
Year and Date
20060724-28
Description
「研究成果報告書概要(欧文)」より
