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Vol.43, No.8, 544 ~ 553, 2005
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| Title |
| Structure and Thermal Stability of Atomic Layer Epitaxy Grown InAs/GaAs (001) Quantum Dots |
| 김형석 H. S. Kim , 서주형 J. H. Suh , 박찬경 C. G. Park , 이상준 S. J. Lee , 노삼규 S. K. Noh , 송진동 J. D. Song , 박용주 Y. J. Park , 최원준 W. J. Choi , 이정일 J. I. Lee |
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| Abstract |
| Self-assembled InAs/GaAs quantum dots (QDs) were grown by atomic layer epitaxy technique and their structure and thermal stability have been studied by using high resolution electron microscopy with in-situ heating experiment capability. The QDs were found to form a hemispherical structure with side facet in the early stage of growth. The average height and diameter of the QDs were found to be ~5 nm and ~23 nm, respectively. Upon capping by GaAs layer, however, the apex of QDs changed to a flat one. In situ heating experiment within TEM revealed that the uncapped QDs remained stable until 580℃. However, at temperature above 600℃, the QDs collapsed due to the diffusion and the evaporation of In and As from the QDs. The density of the QDs decreased abruptly by this collapse and most QDs disappeared at above 600℃. During the observation in a high-voltage electron microscope at high temperature, electron radiation defects, such as twin, stacking faults, amorphization and void, were also generated near surface and propagated into the substrate. |
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| Key Words |
| InAs/GaAs quantum dot, Atomic Layer epitaxy, Thermal stability, Transmission electron microscopy, TEM |
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