Self-assembly of quantum dots: effect of neighbor islands on the wetting in coherent Stranski-Krastanov growth

The wetting of the homogeneously strained wetting layer by dislocation-free three-dimensional islands belonging to an array has been studied. The array has been simulated as a chain of islands in 1+1 dimensions. It is found that the wetting depends on the density of the array, the size distribution and the shape of the neighbor islands. Implications for the self-assembly of quantum dots grown in the coherent Stranski-Krastanov mode are discussed.Comment: 4 pages, 6 figures, accepted version, minor change

Stochastic processes and conformal invariance

We discuss a one-dimensional model of a fluctuating interface with a dynamic exponent $z=1$. The events that occur are adsorption, which is local, and desorption which is non-local and may take place over regions of the order of the system size. In the thermodynamic limit, the time dependence of the system is given by characters of the $c=0$ conformal field theory of percolation. This implies in a rigorous way a connection between CFT and stochastic processes. The finite-size scaling behavior of the average height, interface width and other observables are obtained. The avalanches produced during desorption are analyzed and we show that the probability distribution of the avalanche sizes obeys finite-size scaling with new critical exponents.Comment: 4 pages, 6 figures, revtex4. v2: change of title and minor correction

First-principles calculation of the effect of strain on the diffusion of Ge adatoms on Si and Ge (001) surfaces

First-principles calculations are used to calculate the strain dependencies of the binding and diffusion-activation energies for Ge adatoms on both Si(001) and Ge(001) surfaces. Our calculations reveal that the binding and activation energies on a strained Ge(001) surface increase and decrease, respectively, by 0.21 eV and 0.12 eV per percent compressive strain. For a growth temperature of 600 degrees C, these strain-dependencies give rise to a 16-fold increase in adatom density and a 5-fold decrease in adatom diffusivity in the region of compressive strain surrounding a Ge island with a characteristic size of 10 nm.Comment: 4 pages, 4 figure

Monte carlo simulations of growth modes of Pb nanoislands on Si(111) surface

68.55.-a Thin film structure and morphology, 68.65Hb Quantum dots (patterned in quantum wells, 81.16Dn Self-assembly,