GaSb quantum dots on GaAs with high localization energy of 710 meV and an emission wavelength of 1.3 µm

We report on the epitaxial growth of GaSb quantum dots (QDs) that show photoluminescence at a wavelength of around 1.3 µm and a high hole localization energy of up to 710 meV with a capture cross-section of 1×10−13 cm2. The QDs were grown in Stranski-Krastanov (SK) epitaxial mode with molecular beam epitaxy. The characteristics of these QDs are a high dot density of up to 2.6×1010 cm−2 as well as narrow dot size and dot density distributions. To achieve the desired values for emission wavelength, hole localization energy, and dot density, the influence of the growth parameters must be controlled precisely. The influence of the V/III (i.e. Sb/Ga) partial pressure or flux ratio, growth temperature, nominal coverage, and growth interruption after quantum dot deposition are investigated. The QD samples are analyzed with atomic force microscopy (AFM), photoluminescence (PL), and deep-level transient spectroscopy (DLTS). Theoretical simulations are performed with the nextnano++ software.