One-dimensional alignment of InAs dots on strain-controlled InGaAs layers by selective-area molecular-beam epitaxy

One-dimensional (1D) arrangement of self-organizing InAs dots was demonstrated on strained InGaAs buffer layers grown on mesa-strip-shaped GaAs substrates by molecular-beam epitaxy (MBE). Large anisotropy of strain relaxation in the InGaAs buffer layer was observed by double crystal X-ray diffraction (DCXRD). It was pointed out that misfit dislocations parallel to the stripe edge produce the anisotropic strain, and, as a result, 1D arrangement of InAs dots occurs. The structure of such dot chains depended on the arsenic pressure and the mesa structure including thickness of the buffer layer and the top width of the mesa. In particular, by changing the width of the InGaAs top surface, the number of dot chains could be: controlled one by one. (C) 2000 Elsevier Science B.V. All rights reserved.