Effects of Sb/As Interdiffusion on Optical Anisotropy of GaSb Quantum Dots in GaAs Grown by Droplet Epitaxy

摘要

We studied the effects of Sb/As interdiffusion on the optical anisotropy of GaSb quantum dots (QDs) in GaAs. GaSb QDs were grown by droplet epitaxy, and their shape is slightly elongated along [110]. Polarized photoluminescence (PL) studies showed that the PL is polarized preferentially along [110]. To induce the Sb/As interdiffusion, a post-growth annealing was performed at T_a = 600-950℃. As T_a increases, the degree of polarization (DOP) drastically decreases. The experimental results were compared with a theoretical model. The DOP reduction is explained by considering the optical anisotropy of the ground and first excited states, where the contribution of the excited state increases as the diffusion proceeds.