Monte Carlo simulations of morphological transitions in PbTe/CdTe immiscible material systems

• Published in: Journal of applied physics 2016-09, Vol.120 (12)
• Main Authors: Mińkowski, Marcin, Załuska-Kotur, Magdalena A., Turski, Łukasz A., Karczewski, Grzegorz
• Format: Article
• Language: English
• Subjects: Anisotropy; Applied physics; Computer simulation; Crystal growth; Diffusion; Intermetallic compounds; Lead tellurides; Miscibility; Monte Carlo simulation; Morphology; Multilayers; Nanowires; Phase separation; Quantum dots; Surface diffusion
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4962974

The crystal growth of the immiscible PbTe/CdTe multilayer system is analyzed as an example of a self-organizing process. The immiscibility of the constituents leads to the observed morphological transformations such as an anisotropy driven formation of quantum dots and nanowires and to a phase separation at the highest temperatures. The proposed model accomplishes a bulk and surface diffusion together with an anisotropic mobility of the material components. We analyze its properties by kinetic Monte Carlo simulations and show that it is able to reproduce all of the structures observed experimentally during the process of the PbTe/CdTe growth. We show that all of the dynamical processes studied play an important role in the creation of zero-, one-, two-, and, finally, three-dimensional structures. The shape of the structures that are grown is different for relatively thick multilayers, when the bulk diffusion cooperates with the anisotropic mobility, as compared to the annealed structures for which only the isotropic bulk diffusion decides about the process. Finally, it is different again for thin multilayers when the surface diffusion is the most decisive factor. We compare our results with the experimentally grown systems and show that the proposed model explains the diversity of observed structures.