  Here, we experimentally and theoretically clarify III-V/Si crystal growth
processes. Atomically-resolved microscopy shows that mono-domain 3D islands are
observed at the early stages of AlSb, AlN and GaP epitaxy on Si, independently
of misfit. It is also shown that complete III-V/Si wetting cannot be achieved
in most III-V/Si systems. Surface/interface contributions to the free energy
variations are found to be prominent over strain relief processes. We finally
propose a general and unified description of III-V/Si growth processes,
including the description of antiphase boundaries formation.
