SPAM - Science, Pizza And Mathematics

Phase-field simulation of solid-state dewetting and selective-area growth: arbitrary pattern geometry and crystal faceting

Abstract: The interest toward quantum technologies is driving research to develop devices with high crystalline quality and precise control over their morphologies at the nanoscale. Among the several techniques, growing materials on top of dielectric masks offers the possibility to achieve tailored architectures by exploiting either solid-state dewetting or selective-area growth (SAG) dynamics. This involves a complex interplay between crystal faceting and pattern geometries. To tackle this problem, we discuss a phase-field model comprising both surface diffusion and deposition of a crystalline material on arbitrarily-shaped substrates. In particular an auxiliary order parameter is introduced to map the contact-angle boundary condition on a generic non-planar profile. Extensive three-dimensional simulations of solid-state dewetting of thin layers and nanoparticles are performed (Figure 1), varying both the wetting parameter and crystallographic orientation, testing consistency with Young-Herring Law for faceted shapes. An external flux is then included to reproduce SAG dynamics, inspecting the competition between thermodynamic and kinetic driving forces. The morphological evolution of PbSnTe nanostructures is inspected and compared with experimental data.

Presenter: Emma Radice

TBA

Presenter: TBA