Measurements of Surface Diffusivity and Coarsening during Pulsed Laser Deposition

Pulsed laser deposition (PLD) of homoepitaxial SrTiO₃⟨001⟩ was studied with in situ x-ray specular reflectivity and surface diffuse x-ray scattering. Unlike prior reflecivity-based studies, these measurements access both time and length scales of the evolution of the surface morphology during growth. In particular, we show that this technique allows direct measurements of the diffusivity for both inter- and intralayer transport. Our results explicitly limit the possible role of island breakup, demonstrate the key roles played by nucleation and coarsening in PLD, and place an upper bound on the Ehrlich-Schwoebel barrier for downhill interlayer diffusion.