Misfit Disclinations and Dislocation Walls in a Two-Phase Cylindrical Composite

Abstract

A detailed analysis is given of the conditions for the generation of misfit-induced defects (misfit wedge disclinations and disclination dipoles, periodical arrays of misfit wedge disclinations, and misfit-dislocation walls (MDWs)) in a two-phase cylindrical composite misfitting system. It is shown that the nucleation of the above defects may be favoured in some range of parameters which include substrate and film thicknesses, misfit eigenstrain, and disclination strength or MDW misorientation angle. The limiting case of massive (cylindrical or planar) substrate is specially investigated. The conditions for the misfit defect formation in cylindrical and planar misfitting composites are compared. The peculiarities of misfit defect generation in cylindrical composite systems are briefly discussed.

Elastic interaction between wedge disclination dipole and internal crack

“…The influence of the strength of crystal elastic anisotropy and the position of the dipole on the stress fields was discussed in detail. Sheinerman and Gutkin [8] considered the problems of a misfit wedge disclination dipole in two phase misfitting structure which consists of a cylindrical substrate and a co-axial cylindrical thin film.…”

Wedge disclination dipole in an embedded nanowire within the surface/interface elasticity

“…As a result, in the process of fabrication and utilization, they are subjected to elastic stresses and strains of different origin, which can relax through generation of various defects. For example, it was theoretically shown that misfit strains in the core-shell and embedded nanowires can relax by straight misfit edge [12][13][14][15] and screw [16] dislocations, misfit wedge disclinations and dislocation walls [17], prismatic [14,15,[18][19][20][21] and glide [22] dislocation loops, and penny-shape cracks [21]. Experimental evidence of misfit dislocations was demonstrated in GaP-GaN [23], Ge-Si [24], AlN-GaN [25], and InAs-GaAs [26][27][28] core-shell nanowires.…”

“…[17,). Some of them used atomic simulations [30,37,38,[42][43][44][45], whereas the others dealt with the usual continuum approach within the classical theory of elasticity [17, 29, 31-36, 39-41, 46-51].…”

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…”

“…For example, the symmetric core-shell nanorods ( Fig. 1(i)) can be considered with results obtained for core-shell nanowires (Aifantis et al, 2007;Gutkin et al, 2000;Ovid'ko & Sheinerman, 2004;Sheinerman & Gutkin, 2001;Wang et al, 2010), the nonsymmetric core-shell nanorods ( Fig. 1(h)) with results for nanowires with inclusions (Gutkin et al, 2011), the segmented nanorods ( Fig.…”