III-V antiphase boundaries are not generated by Si or Ge substrate step edges
We critically review recent experimental and theoretical advances on the valence- and structure-mismatched heteroepitaxy of III-V semiconductors on group-IV substrates. We examine key aspects including wetting behavior, atomic configurations at the hetero-interface, substrate passivation, and the stability of antiphase boundaries (APBs). By synthesizing these findings with pioneering studies, we propose a refined description of antiphase boundaries formation. Our analysis shows that hetero-interface formation is dictated by substrate terrace reconstruction, demonstrating that APBs are not generated at monoatomic step edges. This generalized III-V/IV growth framework provides new insights for the integration of III-V semiconductors on group-IV platforms and, more broadly, for valence-mismatched heteroepitaxy.