Multilayered type-II GaSb/GaAs self-assembled quantum dot structure with 1.35μm light emission at room temperature

We have investigated the growth of multilayered type-II GaSb/GaAs self-assembled quantum dot (QD) structure. We show that the key point for the growth of the multilayed GaSb/GaAs QDs lies in how to switch the V elements: Sb and As. It is found that, after the dot deposition, a short exposure to As atmosphere smoothes out the GaSb 3D islands and transforms the structure into 2D-like while the 3D islands remain in an Sb soak. There is a large PL energy separation of 214 meV between the QDs and the corresponding 2D-like structure due to the smoothing-out effect. The PL peak of the multilayered dots is at 1.35μm at room temperature (RT) and only digresses from 1.3μm insignificantly for a broad range of temperature from 13 K to RT.

► A multilayered type-II GaSb/GaAs QD structure was successfully grown by MBE. ► The PL emission of the QDs is at 1.35μm at room temperature. ► The key point for multilayered QD growth lies in how to switch the V elements of Sb and As. ► A short exposure to As smoothes out the dots while an Sb soak makes the dots persistent.