  Pulsed Laser Deposition (PLD) is widely used to grow epitaxial thin films of
quantum materials such as complex oxides. Here, we use in-situ X-ray scattering
to study homoepitaxy of SrTiO$_3$ by energetic (e-) and thermalized (th-) PLD.
We find that e-PLD suppresses the lateral growth of two-dimensional islands,
which suggests that energetic particles break up smaller islands. Fast
interlayer transport occurs for both e-PLD and th-PLD, implying a process
operating on sub-microsecond timescales that doesn't depend strongly on the
kinetic energy of the incident particles.
