Development of cross-hatch grid morphology and its effect on ordering growth of quantum dots |
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Authors: | CL Zhang B Xu ZG Wang P Jin FA Zhao |
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Institution: | Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China |
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Abstract: | We investigate the development of cross-hatch grid surface morphology in growing mismatched layers and its effect on ordering growth of quantum dots (QDs). For a 60° dislocation (MD), the effective part in strain relaxation is the part with the Burgers vector parallel to the film/substrate interface within its component; so the surface stress over a MD is asymmetric. When the strained layer is relatively thin, the surface morphology is cross-hatch grid with asymmetric ridges and valleys. When the strained layer is relatively thick, the ridges become nearly symmetrical, and the dislocations and the ridges inclined-aligned. In the following growth of InAs, QDs prefer to nucleate on top of the ridges. By selecting ultra-thin In0.15Ga0.85As layer (50 nm) and controlling the QDs layer at just formed QDs, we obtained ordered InAs QDs. |
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Keywords: | A1 Stress A1 Nanostructures A1 Surface structure A3 Molecular beam epitaxy B2 semiconducting III– V materials |
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