Hillock-free and atomically smooth InSb QWs grown on GaAs substrates by MBE

•Surface morphology of InSb QWs was studied as a function of GaAs substrate offcut.•Hillock-free morphology was achieved when substrate offcut matches hillock facet.•Atomically smooth morphology was achieved for the entire wafer of InSb QWs. Comprehensive studies on the surface morphological evolution of AlInSb metamorphic buffers and InSb QWs grown on top were conducted as a function of the GaAs (001) substrate offcut angles. We confirmed our earlier postulation that the vicinal surfaces defined by the hillock facets have the exact surface orientation needed to achieve large-area hillock-free surfaces. The related morphological transitions were discussed with a graphic illustration. The optimum substrate offcut for InSb towards [1¯10] direction was found to be around 0.5–0.6° with our growth conditions. On 2-inch GaAs (001) substrates with this offcut, a hillock-free and atomically smooth surface morphology was successfully achieved for modulation-doped InSb QWs.