Study of nucleation positions of InAs islands on stripe-patterned GaAs (1 0 0) substrate

By combination of prepatterned substrate and self-organized growth, InAs islands are grown on the stripe-patterned GaAs (1 0 0) substrate by solid source molecular beam epitaxy. Four [0 1 1bar] stripe-patterned substrates different in pitch, depth, and sidewall angle, respectively, are used in this work. The surface morphology obtained by atomic force microscopy shows that the InAs quantum dots can be formed either on the ridge or on the sidewall of the stripes near the bottom, depending on the structure of the stripes on the patterned substrate. The mechanism determining the nucleation position of the InAs dots is discussed. The optical properties of the InAs dots on the patterned substrates are also investigated by photoluminescence.