Spatially ordered self-assembled quantum dots with uniform shapes fabricated by patterning nanoscale SiN islands

We report a method of obtaining position-controlled quantum dots with the uniform spatial shapes. The self-assembled InGaAs quantum dots are grown on a GaAs (311) B substrate with patterned SiN islands. The SiN patterns determine the position of the quantum dots as well as their optical properties. The uniformity of the positions and photoluminescence properties strongly depend on the pitch of the hexagonally patterned SiN islands. With an optimum pattern, the quantum dots have a uniform spatial arrangement. These uniform quantum dots exhibit strong photoluminescence spectra with sharp peaks and spatially isotopic polarization resolved photoluminescence signals. These results show that quantum dots have efficient photoemission processes and that their shapes have the same spatial symmetry.