| Project/Area Number |
07555098
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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 | 試験 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUKATSU Susumu The University of Tokyo, Graduate School of Arts and Sciences, Associate Professor, 大学院・総合文化研究科, 助教授 (60199164)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Tatsuo The University of Tokyo, Graduate School of Arts and Sciences, Research Associat, 大学院・総合文化研究科, 助手 (00242016)
ITO Ryoichi The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (40133102)
KOMIMYAMA Susumu The University of Tokyo, Graduate School of Arts and Sciences, Professor, 大学院・総合文化研究科, 教授 (00153677)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1995: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | Indirect-gap Semiconductors / SiGe-based Quantum Wells / Si / SiO_2-ended Microcavity / Spontaneous Emisson Control / Radiative Lifetimes / 0-dimensional Confienment / Suppression of Phonon-aided Transitions / Intermediate States / SiGe歪混晶量子井戸 / キャビティ量子井戸 / フォノン介在遷移制御 / 時間分解測定 / 励起子効果 / 非フォノン過程自然放出 / 発光寿命短縮 / 誘導放出光発生 |
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| Research Abstract |
The chief objective is to pave the way for the realization of an inverted population in an attempt to generate stimulated emissions in SiGe-based indirect-gap quantum wells by exploiting the state-of-the-art epitaxy and advanced quantum electronics.
To this end, much efforts were directed toward the epitaxial cavity formation to control the spontaneous emission. Highly-reflective Si/Sio_2 Bragg mirrors and a one-wavelength well-centered microcavity were fairly successful. A infrared-enhanced photomultiplier allowed the observation of a luminescence lifetime difference between edge- and surface-emissions.
Apart from cavity-based manipulation, a total suppression of phonon-aided spectra was demonstrated using interface-engineering. Three-dimensional Ge islands were used as quantum dots to break the translational symmetry thereby removing the otherwise strict momentum conservation. Prolonged radiative lifetimes were in support of a k-diagonal radiative recombination as expected.
As to indire
… More
ct-exciton recombinations, much was newly found ; A large anisotropy for the edge emissions, the missing light-cone limitations on thermalization, a large Coulomb screening, an enhanced band-gap renormalization, a lifetime reduction due to 2-D confinement, the masked quantum-confined Stark effects, and etc.
For comparative purposes, the zone-folded superlattice was revisited in an attempt to rectify misleading concepts. Significance of structural disorders which would intimidate the predicted luminescence properties was pointed out. An ordered short-period superlattice was found to be inevitably transformed into a disordered one due to a large inhomogeneous witdth and a narrow miniband of the ground state.
From technical standpoint, device characteristics were also atudied. Dynamical backscattering was observed for a quantum-well potential. A virtual blocking was confirmed by monitoring time-reolved spectra. Furthermore, the Si-SiO_2 technique was extended for the fabrication of orderly Si dots for use as light emitters replacing SiGe quantum wells. Less
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