SELF-ORGANIZED GROWTH OF REGULAR NANOMETER-SCALE INAS DOTS ON GAAS

The deposition of InAs on GaAs proceeds first by two-dimensional (2D) growth and above a 1.75-monolayer coverage by the formation of single-crystal dots on a residual 2D wetting layer. By atomic force microscopy measurements, we show that the first dots formed are in the quantum size range (height 30 Angstrom half-base 120 Angstrom), that the dispersion on their sizes is remarkably low (+/- 10%), and that they are located fairly regularly (interdot distance 600 Angstrom). Upon further growth, density and shapes do not change but sizes increase up to double values before coalescence occurs. Self-organized growth in strained structures is then shown to be a simple and efficient way of building regular quantum dots.