Finite element modelling of strained nanowire heterostructures

University essay from Lunds universitet/Synkrotronljusfysik; Lunds universitet/Fysiska institutionen

Abstract: When two materials with different lattice constants are grown together, this generates stress between them, and therefore strain. This strain causes them to have different thermal and electrical properties, and this is especially important on the nanoscale where changes have large impacts. This project is intended to see if COMSOL can be used as a tool to model how materials respond to lattice mismatch induced strain. One nanowire consisting of three segments was generated. One middle segment of indium phosphide surrounded by indium gallium phosphide, based on locally made nanowires. It is also intended to serve as a base point for further direct research based on data points generated from the project's simulations. The COMSOL Multiphysics' engine is used to generate simulations of nanowires using a Finite Element Method. The goal with this work is as a demonstration of how this can be easily replicated in the future. The variables tested were wire radius, the thickness of the middle InP, and percentage gallium in the InGaP segments. The results of the simulations match the theory well, but due to time and scope constraints they could not be compared to the experimental nanowires used as a foundation for the project, so this should be treated as a first step in determining how useful COMSOL is for practically modelling nanowires.

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