Abstract
We investigate different growth techniques of InSb quantum dots in a GaSb matrix for applications in laser devices operating in the mid-infrared region. We show that conventional molecular beam epitaxy growth does not provide an active medium suitable for device applications, due to the very long migration length of In-adatoms on Sb-terminated surfaces. For this reason, we developed an innovative growth technique, consisting of a deposition at an extremely low temperature followed by a properly designed annealing step. In this way, the In-adatoms mobility is strongly reduced and the control of the island evolution allows us to achieve good morphological and structural properties, with a density of strained and defect-free islands as high as 7×1010 cm−2. These nanostructures exhibit narrow PL emission up to room temperature around 3.4 μm.