Modeling the plastic relaxation onset in realistic SiGe islands on Si(001)

Abstract

A detailed investigation of plastic relaxation onset in heteroepitaxial SiGe islands on Si͑001͒ is presented. The strain field induced by a straight misfit-dislocation segment is modeled by finite-element-method ͑FEM͒ calculations in three dimensions, fully taking into account the interaction with the multifaceted free surfaces of realistic islands. The total elastic energies before and after the placement of a 60°dislocation segment in the most favorable position are therefore evaluated by a full FEM approach, for different island sizes and compositions. The critical volumes with composition for inserting the dislocation are finally obtained and successfully compared with the data in a report by Marzegalli et al. ͓Phys. Rev. Lett. 99, 235505 ͑2007͔͒, where experimental values are compared to a simpler approach.

Photodetection in Hybrid Single-Layer Graphene/Fully Coherent Germanium Island Nanostructures Selectively Grown on Silicon Nanotip Patterns

“…The dislocation-induced deformation was solved in 2D in the central section of the nanostructures, considering the effect of an infinitesimal 60°-dislocation segment placed at the interface (as in Ref. 47 ). Then it was superimposed to the coherent elastic field in the same section that was obtained from a full 3D calculation (see Supporting Information for details).…”

Calculation of the bending area of threading dislocations of InGaAs quantum dots on a GaAs substrate

“…Compared with other approaches [10][11][12], the proposed method avoids discontinuity at the dislocation core and can be extended carefully to any material with varying shapes of QDs and types of dislocations.…”

“…An analytical approach that assumes that the dislocation is position-independent has been applied to InGaAs/GaAs QDs [10]; however, this approach has since been proven inaccurate [11]. Taking into consideration the effects of the position of the dislocation, we simulated the TD filtering mechanism using gallium nitride (GaN) QDs [12].…”

Misfit stress relaxation in composite nanoparticles

“…For example, the misfit strain, which is a special type of residual strains caused by the difference in lattice parameters of crystals in contact, changes the energy gap in semiconductor nanoparticles (quantum dots) embedded in epitaxial layers (Andreev & O'Reilly, 2000;Bimberg, Grundmann, & Ledentsov, 1996;Peng et al, 2005), thus modifying the electronic and optical properties of light-emitting devices (injection lasers and light-emitting diodes) on quantum dots. On the other hand, the residual strains and stresses in CNPs can relax through generation of various defects, in particular, misfit dislocations as is the case with planar heteroepitaxial structures (Beanland, Dunstan, & Goodhew, 1996;Fitzgerald, 1991;Freund & Suresh, 2003;Gutkin, Kolesnikova, & Romanov, 1993;Jain, Willis, & Bullough, 1990;Jain, Harker, & Cowley, 1997;Matthews, 1979;Van der Merwe, 1991;Vdovin, 1999), nanoislands on substrates (Chen et al, 1996;Gatti, Marzegalli, Zinovyev, Montalenti, & Miglio, 2008;Liu, Ross, & Schwarz, 2000;Ovid'ko & Sheinerman, 2006;Wang et al, 2011;Zou, Liao, Cockayne, & Jiang, 2002), quantum dots Chaldyshev, Bert, Kolesnikova, & Romanov, 2009;Kolesnikova & Romanov, 2004a, 2004bKolesnikova, Romanov, & Chaldyshev, 2007;Ovid'ko & Sheinerman, 2006) and wires (Gosling & Willis, 1995;Gutkin, Ovid'ko, & Sheinerman, 2003;Ovid'ko & Sheinerman, 2006) in epitaxial layers, core-shell (Aifantis, Kolesnikova, & Romanov, 2007;Gutkin, Ovid'ko, & Sheinerman, 2000;Goldthorpe, Marshall, & McIntyre, 2008;Kavanagh, 2010;Sheinerman & Gutkin, 2001;Ovid'ko & Sheinerman, 2006…”