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The paper presents a multiscale study of the kinetic processes of the heteroepitaxial growth of the PbSe/PbTe (111) and PbTe/PbSe(001) systems, using the Concurrent Atomistic-Continuum (CAC) method as the simulation tool. The CAC simulations have reproduced the Stranski–Krastanov growth mode and the layer-by-layer growth mode of the two systems, respectively; the pyramid-shaped island morphology of the PbSe epilayer on PbTe (111), the square-like misfit dislocation networks within the PbTe/PbSe(001) interface, and the critical thickness for the PbTe/PbSe(001) system at which coherent interfaces transit to semi-coherent interfaces with the formation of misfit dislocations, all in good agreement with experimental observations. Four types of misfit dislocations are found to form during the growth of the two PbTe/PbSe heterosystems, and hexagonal-like misfit dislocation networks are observed within the PbSe/PbTe(111) interfaces. The growth processes, including the formation of misfit dislocations, have been visualized. Dislocation half-loops have been observed to nucleate from the epilayer surfaces. These half-loops extend towards the interface by climb or glide motions, interact with other half-loops, and form misfit dislocation networks at the interfaces and threading dislocations extending from interfaces to epilayer surfaces. The dominant types of misfit dislocations in both systems are found to be those with Burgers vectors parallel to the interfaces, whereas the misfit dislocations with Burgers vectors inclined to the interface have a low likelihood of generation and tend to annihilate. The size of the substrate is demonstrated to have a significant effect on the formation, evolution, and distribution of dislocations on the growth of PbSe on PbTe(111).
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Effects of misfit dislocations and dislocation mobility on thermal boundary resistance of PbTe/PbSe interfaces
We present a molecular dynamics study of the thermal transport properties of PbTe/PbSe (111) and PbTe/PbSe (100) interfaces at room temperature. The PbTe/PbSe heterostructures are obtained through simulations of the kinetic processes of direct bonding of PbTe and PbSe crystals. The atomic-scale dislocation core structures and the misfit dislocation networks in the heterostructures obtained in the simulations are found to closely match experimental data. Two types of heat transfer experiments are then simulated: a heat-sink heat-source experiment and an ultrashort heat pulse experiment. Thermal boundary resistance is calculated for three distinct interface types: coherent, semi-coherent, and semi-coherent with pinned dislocations. Both types of simulations consistently capture the significant role of the misfit dislocations on thermal resistance. The effect of the mobility of dislocations on thermal resistance is demonstrated for the first time through comparing the thermal boundary resistance of interfaces containing pinned dislocations and with those containing unpinned dislocations. In addition, the thermal boundary resistance is found to strongly depend on the length of the specimen and the area of the interface.
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- PAR ID:
- 10528827
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Computational Materials Science
- Volume:
- 235
- Issue:
- C
- ISSN:
- 0927-0256
- Page Range / eLocation ID:
- 112828
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.commatsci.2024.112828
