The Nature and Origin of Lateral Composition Modulations in Short-Period Strained-Layer Superlattices

Abstract

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Detecting lateral composition modulation in dilute Ga(As,Bi) epilayers

“…Importantly, the data interpretation is relatively straightforward for this purpose [21]. HRXRD has been successfully applied in the investigation of laterally modulated structures like (InAs) n /(AlAs) m (m ≈ n) shortperiod superlattices [22][23][24][25], where strong satellite peaks due to LCM are observed. These strong satellite peaks can reliably serve as a sign of the occurrence of LCM and can even provide quantitative information about those structures, therefore offering prompt feedback.…”

Wetting effect and morphological stability in growth of short-period strained multilayers

“…This stress-driven morphological instability can lead to lateral compositional modulations in vertical short-period superlattices, 1,2,3,4 as a result of layer thickness modulations (caused by interface rippling) and different material components in adjacent layers. 3,5 The spontaneous formation of these lateral modulations is also a promising way to self-organize fabrication of low-dimensional quantum heterostructures, especially quantum wires. 1,2,3 Although understanding of the detailed growth mechanism in multilayer structures is important and of much interest for both fundamental studies and device applications, it is still far from complete due to the complexity of the system.…”

“…3,5 The spontaneous formation of these lateral modulations is also a promising way to self-organize fabrication of low-dimensional quantum heterostructures, especially quantum wires. 1,2,3 Although understanding of the detailed growth mechanism in multilayer structures is important and of much interest for both fundamental studies and device applications, it is still far from complete due to the complexity of the system. This complexity arises from the coupling of strain fields in different layers, and the nonequilibrium nature of the growing film for which material deposition rates play an important role in the pattern formation.…”

“…In the following these general results, which can apply to both periodic and nonperiodic systems, are used to determine the morphological stability of periodic tensile/compressive multilayer structures, and in particular shortperiod superlattices. 1,2,3,4 In this case the multilayer film is composed of alternating A and B layers, with their associated parameters such as nonzero misfits ǫ * A(B) , layer thicknesses l * A(B) , surface mobilities Γ * A(B) , deposition rates v * A(B) and surface stiffnesses γ * A(B) . Here we have expressed all the parameters in dimensionless form:…”

“…1, where in order to compare with experiments, the parameters are chosen to qualitatively represent those of the growth of AlAs/InAs/InP(001) short-period superlattices. 3,4 Note that the global strain of the whole multilayer film can be defined as…”