Formation of self-organized In_0.5Ga_0.5As quantum dots on GaAs by molecular beam epitaxy

Self-organized In_0.5Ga_0.5As quantum dots have been successfully grown on vicinal GaAs substrates by molecular beam epitaxy. The density of the quantum dots can be changed by nucleating the dots under different As overpressure. Substrate tilt angle of 15° results in much larger dot size and density than that of 4° due to the closely spaced step edges on the surface. Through investigations of the dots grown on In_0.1Ga_0.9As buffer, the strain energy of the buffer layer is also found to be an important factor that affects the size and density of the quantum dots.