Effect of material anisotropy on the self-positioning of nanostructures

Abstract

An experimental and numerical investigation of the effect of material anisotropy on the self-positioning of epitaxial nanostructures has been performed. The self-positioning occurs due to a lattice mismatch between two epitaxial material layers (GaAs and In(0.2)Ga(0.8)As) of a hinge. Both materials have cubic crystal symmetry and possess anisotropic mechanical properties. The dependence of the hinge curvature radius on the material orientation angle was obtained experimentally by creating self-positioning hinges with different angles between the hinge axis and material crystallographic axes. The same self-positioning structures were modelled by solving geometrically nonlinear problems with the help of the finite element method. Experimental and numerical values of the hinge curvature radius are in qualitative agreement. It is found that material anisotropy significantly affects the shape of self-positioning structures.

Continuum and Atomic-Scale Modeling of Self-Positioning Microstructures and Nanostructures

“…For varying orientation angles, the ratio of maximum and minimum values of the curvature radius is about 1.35. This ratio is similar to experimental data and numerical finite element modeling of GaAs and In 0.2 Ga 0.8 As bi-layer structures [12]. Dependency of the curvature radius on the material orientation angle is close to sinusoidal function with frequency π.…”

“…It is assumed that rotations and translations are large but strains are small. Our algorithm [12] includes both material anisotropy and large displacements. Usually, geometrical nonlinearity and anisotropy are treated separately [13,14].…”

“…Here we investigate effect of material anisotropy on the curvature radius of selfpositioning structures and compare results with experimental data [12]. The hinged A three-dimensional mesh for the symmetrical half of the structure consists of 555 hexahedral 20-node elements and 3125 nodes.…”

Generalized plane strain deformation of multilayer structures with initial strains

“…In this section, the obtained analytical generalized plane strain solution is compared with the ordinary plane strain solution [15] and with results obtained by the finite element analysis. Details about finite element procedures for self-positioning micro-and nano-structure can be found in publications of Nikishkov et al [17,18]. For comparison of results, we model a bilayer structure as shown in Fig.…”

Atomic-Scale Analysis of Self-Positioning Nanostructures

“…Analytical solutions have been derived based on continuum mechanics theory to predict the curvature radius [10][11][12]. Computational modeling has been also performed to understand characteristics of self-positioning nanostructures [13][14][15][16]. However, just few publications investigate selfpositioning structures taking into account atomic-scale effects.…”