Control of GaSb/GaAs Quantum Nanostructures by Molecular Beam Epitaxy

GaSb quantum wells (QWs) and quantum dots (QDs) were fabricated on GaAs(001) surfaces by molecular beam epitaxy. By scanning transmission electron microscopy and photoluminescence (PL) measurements, their nanostructures were evaluated. One-monolayer-thick GaSb was precisely formed by the surface exchange reaction between As and Sb atoms, which was monitored by reflection high-energy electron-beam diffraction. In the Stranski-Krastanov growth of the GaSb QDs, low growth rate and low Sb4 pressure were effective conditions for suppressing size fluctuation. As a result, we could obtain the narrowest PL linewidth of 67 meV for GaSb/GaAs QDs.