Misfit dislocations in multilayered films on disclinated substrates

Abstract

A theoretical model which describes the generation of misfit dislocations in multilayered films deposited onto plastically deformed substrates with disclinations (defects of rotational type) is suggested. In the framework of the model, the ranges of the parameters (disclination strength, misfit parameters, layer thicknesses, characteristics of disclination arrangement) of a multilayered film/substrate composite for which the generation of misfit dislocations is energetically favourable are calculated. The specific features of the generation of misfit dislocations in multilayered films on disclinated substrates are discussed in relation to a technologically interesting possibility for exploiting plastically deformed substrates.

Misfit dislocations in composites with nanowires

“…In general, these misfit stresses can be relaxed via the generation of various defect configurations, such as isolated misfit dislocations, misfit dislocation dipoles, prismatic dislocation loops and semi-loops. Similar to misfit defects in conventional continuous films and film islands (see, e.g., [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]), the formation of misfit defect configurations in nanowires is energetically favourable in certain ranges of parameters of the composite system under consideration.…”

“…Generation and evolution of misfit dislocations are crucially affected by geometric parameters of constituent phases of composites. The effect of the geometric parameters on behaviour of misfit dislocations is the subject of intensive experimental and theoretical studies which commonly deal with plate-like, continuous and island films deposited onto substrates, e.g., [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. However, with the rapidly growing attention to composites containing nanowires, it is highly interesting to analyse the behaviour of misfit dislocations in such composites.…”

Competing relaxation mechanisms in strained semiconducting and superconducting films

“…Finally, the energy E −d 2 that characterizes the interaction between disclinations and dislocations is calculated using formula [17] as follows:…”

“…In many cases, defects in solid films are generated, causing relaxation of misfit stresses that occur due to geometric mismatch between crystal lattice parameters of films and substrates. The most widespread physical mechanisms for relaxation of misfit stresses in continuous and island films are associated with the formation of misfit dislocations and their complicatedly arranged configurations; see, e.g., [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. However, non-conventional misfit defectsmisfit disclinations (rotational defects)-are also capable of causing effective relaxation of misfit stresses; see the experimental data [21][22][23][24][25] and theoretical models [26][27][28][29][30].…”

Nanograins with 90° grain boundaries in high transition temperature superconducting films

“…The boundaries between a nanograin and the film matrix are capable of being stress sources that compensate, in part, for misfit stresses. In this context, the formation of nanograins represents a new mechanism for relaxation of misfit stresses, which serves as an effective alternative to conventional relaxation mechanisms (see, for example, review articles [26][27][28][29][30][31][32][33][34][35][36][37][38]) related to the formation of misfit dislocations and their configurations in strained films.…”