Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

• Main Authors: Fernández-Delgado, Natalia, Collado, Miriam Herrera, Chisholm, Matthew F., Ahmad Kamarudin, Mazliana, Zhuang, Qian Dong, Hayne, Manus, Molina, Sergio I.
• Format: Article
• Language: English
• Published: Elsevier 2017
• Online Access: http://psasir.upm.edu.my/id/eprint/15114/1/Effect%20of%20an%20in-situ%20thermal%20annealing%20on%20the%20structural%20properties%20of%20self-assembled%20GaSbGaAs%20quantum%20dots.pdf; http://psasir.upm.edu.my/id/eprint/15114/; https://www.sciencedirect.com/science/article/pii/S016943321630914X#!

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.