Evolution mechanism of heterointerface cross-section during growth of GaAs ridge quantum wires by selective molecular beam epitaxy

The mechanism determining heterointerface cross-sections is studied for GaAs ridge quantum wires (QWRs) grown by selective molecular beam epitaxy (MBE). Arrays of h-1 1 0i- and h-1 -1 2i-orientated QWRs were grown on (0 0 1) and (1 1 1)B GaAs patterned substrates, respectively. A detailed investigation of cross-sections of wires has shown that the boundary planes appear on both sides of QWRs, keeping a constant angle, y, with respect to the flat top of the substrate pattern, and they determine the lateral wire width. Their evolution mechanism has turned out to be a kinetic process, reflecting differences in migration and atom incorporation rates on different facets. Simple formulas for y have been derived, and they have shown excellent agreements with experiment. This has led to precise kinetic control of the wire width by growth conditions. # 2004 Elsevier B.V. All rights reserved