Coherent islands and microstructural evolution

Low-Dimensional Group III-V Compound Semiconductor Structures

“…An initial broadening and subsequent narrowing reported 53,76,77 for near equilibrium islands further suggests that this nature of island evolution is a general phenomenon occurring over the entire range from highly kinetically controlled regime to near thermodynamic equilibrium. The above remarkable findings in this carefully controlled series of systematic experiments thus not only provide stringent tests for models 33,60,78,81 of strained epitaxy and island formation but also provide insights into the nature of atomistic kinetic processes 33,78 consistent with the observations. The observed initial broadening in the island lateral size distribution and increase in average size up to island density of ~24 m -2 can be understood if, at the earliest stages, the 3D island initiation rate is constant and their growth rates are independent of each other.…”

Evolution of GaSb epitaxy on GaAs(001)-c(4×4)

“…9 Hence, the larger the 3D structures are when they merge, the fewer threading dislocations there should be in the resulting continuous film ͑i.e., if the growth of a low density of large dots can be promoted, the final dislocation density should decrease͒. Recalling that once a quantum dot relaxes it becomes the lowest energy site for further growth, 18 growing at a reduced rate and higher temperature should promote growth on relaxed regions by inhibiting the nucleation of new dots and enhancing the adatom diffusion rate. This prediction is supported by the observations that with increasing growth temperature the size of 3D InAs islands on GaAs increases, 5 and the density of threading dislocations in thick AlSb films on GaAs decreases.…”

“…Once a dot relaxes, it then becomes a low-energy site for future growth, both from further deposition and from the decay of nearby strained dots ͑i.e., Ostwald ripening͒. 18 The preferential growth of these relaxed 3D structures leads to rapid, uneven film growth and adjacent dot coalescence. As the film thickness increases, the relaxed regions continue to grow rapidly FIG.…”

Lateral and vertical ordering in multilayered self-organized InGaAs quantum dots studied by high resolution x-ray diffraction

“…The homogeneity of the island size depends on the strain energies involved, which can induce a limiting island size. 9 A fields which extend into the barrier material. 11,12 In Ref.…”