Predictions of Wulff-Kaischew equilibrium shapes during heteroepitaxial Growth of III-V on Si: DFT and in-situ Experiments

A fundamental understanding of heteroepitaxial growth requires a deep knowledge of nucleation at the atomistic level, which is crucial for advanced optoelectronic and photoelectric semiconductor applications [1, 2]. Here, we use theoretical DFT calculations as well as advanced growth and in-situ microscopy tools to propose a comprehensive first-principles atomistic approach to predict the Wulff-Kaischew equilibrium shape of crystals heterogeneously integrated on dissimilar substrates. First, we show how the absolute surface and interface energies can be determined, and assess their variations with the chemical potential for GaP on Si [3, 4]. We highlight the strong impact of surface passivation on the wetting properties of GaP on Si, promoting a 3D Volmer-Weber growth mode [5]. Finally, we explore the potential of a fully ab initio Wulff-Kaischew equilibrium crystal shape approach, and confront it with transmission electron microscopy experiments performed in situ during the growth, which significantly enhances the understanding of growth processes and the physical properties of hetero-integrated materials and devices [6].