Fernández-Delgado, N. and Herrera, M. and Chisholm, M. F. and Ahmad Kamarudin, Mazliana and Zhuang, Qiandong and Hayne, Manus and Molina, S. I. (2017) Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots. Applied Surface Science, 395. pp. 136-139. ISSN 0169-4332
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Abstract
In this work, the effect of the application of a thermal annealing on the structural properties of GaSb/GaAs quantum dots (QDs)1 is analyzed by aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM)2 and electron energy loss spectroscopy (EELS)3. Our results show that the GaSb/GaAs QDs are more elongated after the annealing, and that the interfaces are less abrupt due to the Sb diffusion. We have also found a strong reduction in the misfit dislocation density with the annealing. The analysis by EELS of a threading dislocation has shown that the dislocation core is rich in Sb. In addition, the region of the GaAs substrate delimited by the threading dislocation is shown to be Sb-rich as well. An enhanced diffusion of Sb due to a mechanism assisted by the dislocation movement is discussed.