Abstract: The nanotechnology based on epitaxial systems
includes single or arranged misfit dislocations. In general, whatever
is the type of dislocation or the geometry of the array formed by the
dislocations; it is important for experimental studies to know exactly
the stress distribution for which there is no analytical expression [1,
2]. This work, using a numerical analysis, deals with relaxation of
epitaxial layers having at their interface a periodic network of edge
misfit dislocations. The stress distribution is estimated by using
isotropic elasticity. The results show that the thickness of the two
sheets is a crucial parameter in the stress distributions and then in the
profile of the two sheets.
A comparative study between the case of single dislocation and
the case of parallel network shows that the layers relaxed better when
the interface is covered by a parallel arrangement of misfit.
Consequently, a single dislocation at the interface produces an
important stress field which can be reduced by inserting a parallel
network of dislocations with suitable periodicity.
Abstract: The present work is motivated by the idea that the
layer deformation in anisotropic elasticity can be estimated from the
theory of interfacial dislocations. In effect, this work which is an
extension of a previous approach given by one of the authors
determines the anisotropic displacement fields and the critical
thickness due to a complex biperiodic network of MDs lying just
below the free surface in view of the arrangement of dislocations.
The elastic fields of such arrangements observed along interfaces
play a crucial part in the improvement of the physical properties of
epitaxial systems. New results are proposed in anisotropic elasticity
for hexagonal networks of MDs which contain intrinsic and extrinsic
stacking faults. We developed, using a previous approach based on
the relative interfacial displacement and a Fourier series formulation
of the displacement fields, the expressions of elastic fields when
there is a possible dissociation of MDs. The numerical investigations
in the case of the observed system Si/(111)Si with low twist angles
show clearly the effect of the anisotropy and thickness when the
misfit networks are dissociated.