Spontaneous nanostructure formation on GaAs(211)B substrate

Our study of metalorganic vapor-phase epitaxy grown self-assembled In0.5Ga0 .5As quantum structures on GaAs(2 1 1)B substrate showed strong shape depen dence on growth temperature (T-g). Small In0.5Ga0.5As islands grown at 510 degrees C coalesce, forming a wire structure in the [0 1 1] direction with increasing T-g up to 630 degrees C. At T-g exceeding 650 degrees C, the str ucture changes to large, asymmetric islands consisting of facets minimizing emerging surface energy. In addition, quantum dot (QD) size uniformity is improved with an increase in T-g. After the GaAs buffer layer growth at T-g range exceeding 670 degrees C, surface shows straight, a uniform saw-tooth corrugation consisting of (3 1 1)B and (3 2 2)B terraces. QDs do form on t he(3 1 1)B surface, not on the(3 2 2)B surface. Using selective area QD for mation, well-aligned rows of QDs were fabricated on (2 1 1)B substrates. (C ) 1999 Elsevier Science B.V. All rights reserved.