Highly polarized self-assembled chains of single layer InP/(In,Ga)P quantum dots

Well-ordered chains of InP quantum dots on a self-organized undulating $In0.48Ga0.52P$ surface exhibit optical anisotropy due to their shape and the $In0.48Ga0.52P$ matrix. The structures are investigated by polarization-dependent photoluminescence together with transmission electron microscopy. Luminescence from the $In0.48Ga0.52P$ matrix is polarized in one crystallographic direction due to anisotropic strain arising from a lateral compositional modulation. The photoluminescence measurements show enhanced linear polarization in the alignment direction of quantum dots, $[1¯10]$⁠. A polarization degree of 66% is observed; this polarization in emission is independent of the polarization of the excitation laser. The optical anisotropy is achieved with a straightforward heterostructure, requiring only a single layer of QDs.