Scaling of Heteroepitaxial Island Sizes
نویسندگان
چکیده
Monte Carlo simulations of an atomistic solid-on-solid model are used to study the effect of lattice misfit on the distribution of two-dimensional islands sizes as a function of coverage Θ in the submonolayer aggregation regime of epitaxial growth. Misfit promotes the detachment of atoms from the perimeter of large pseudomorphic islands and thus favors their dissolution into smaller islands that relieve strain more efficiently. The number density of islands composed of s atoms exhibits scaling in the form Ns(Θ) ∼ Θ/〈s〉2 g(s/〈s〉) where 〈s〉 is the average island size. Unlike the case of homoepitaxy, a rate equation theory based on this observation leads to qualitatively different behavior than observed in the simulations. PACS: 05.70.Ln,68.55.-a,82.20.Mj † Also at The Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom; on leave from the Institute of Physics, Czech Academy of Science, Cukrovarnická 10, 16200 Praha 6, Czech Republic.
منابع مشابه
Anomalous scaling in heteroepitaxial island dynamics on Ag(100).
Diffusion and decay of alloyed Cu/Ag islands are investigated in the size range from 1 to 40 nm2 on Ag(100) at room temperature with fast-scanning tunneling microscopy and density functional theory. While islands at sizes above 7 nm2 show the diffusion and decay behavior expected for dynamics based on single atom hopping, islands smaller than 4 nm2 diffuse faster and decay slower than predic...
متن کاملStudy of island formation in epitaxially strained films on unbounded domains
We consider a variational model related to the formation of islands in heteroepitaxial growth on unbounded domains. We first derive the scaling regimes of the minimal energy in terms of the volume of the film and the amplitude of the crystallographic misfit. For small volumes, non-existence of minimizers is then proven. This corresponds to the experimentally observed wetting effect. On the othe...
متن کاملStrain versus Dislocation Model for Understanding the Heteroepitaxial Growth of Nanowires
In this paper, we adapted the Stranski-Krastanow (SK) mode to the heteroepitaxial growth of NWs and suggested three general growth modes (SK, island SK, and coherent SK) covering all phenomena observed from nanostructures epitaxially grown on single crystal substrates. A strain versus dislocation (SVD) model was also established to define these three modes. The SVD model analyzes the competitio...
متن کاملSculpting semiconductor heteroepitaxial islands: from dots to rods.
In the Ge on Si model heteroepitaxial system, metal patterns on the silicon surface provide unprecedented control over the morphology of highly ordered Ge islands. Island shape including nanorods and truncated pyramids is set by the metal species and substrate orientation. Analysis of island faceting elucidates the prominent role of the metal in promoting growth of preferred facet orientations ...
متن کاملScaling of submonolayer island sizes in surfactant-mediated epitaxy of semiconductors
We study submonolayer island size distributions in the epitaxy of Si and Ge on the Si(111) surface with Bi as a surfactant. We show that sizes of Si islands at different growth temperatures scale to a standard scaling function that peaks at the mean island size. Size distribution of Ge islands demonstrates qualitatively different behavior: With the decreasing temperature the most probable size ...
متن کامل