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Medium scale modeling of the CdTe/ZnTe islands the empirical potential and finite element approach

Piotr Traczykowski 2Slawomir Kret 1Piotr Dłużewski 1Paweł Dłużewski 2Sebastian Maćkowski 1Grzegorz Karczewski 1

1. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland
2. Polish Academy of Sciences, Institute of Fundamental Technological Research (IPPT PAN), Świętokrzyska 21, Warszawa 00-049, Poland


Precise determination of the size, shape and composition of nanosize coherent islands obtained by MBE growth of CdTe/ZnTe heterostructures is important to understand the formation mechanizms and optical properties of such objects.
The Stillinger-Weber interatomic potential have been used to perform medium scale computer simulation of the island structure, which is in good agreement with experimental high resolution transmission electron microscopy (HRTEM) cross-sectional and planar view images
We use Finite Element solver to calculate atoms position of elliptical shaped island in the box containing up to 100000 atoms. In this approach we describe bonds as pseudoelements and restrict calculations to two types of them: 2-node, which model interaction between 2(1 bond) atoms and 3-node, which model interaction between 3-atoms (2 bonds). Novel mesh generator was developed for creation of the pseudoelements compatible with standard Finite Element routines.
The boundary conditions coming from geometry of TEM specimen were applied. The generated mesh was used to Finite Element Solver and equilibrium atoms positions were obtained in the sense of molecular static. Such atoms positions were used for simulation of the HRTEM images.
In this paper we give the initial model of CdTe/ZnTe, which match qualitatively with HRTEM observation. More precise results can be obtained by feed back approach with quantitative comparison of the simulated and experimental images.
This calculation method can be extended to large scale calculation to simulate growth of quantum dots stack or initiation of dislocations between epitaxial layers.


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Presentation: poster at E-MRS Fall Meeting 2003, Symposium C, by Piotr Traczykowski
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-27 17:58
Revised:   2009-06-08 12:55