Measurements of Surface Diffusivity and Coarsening During Pulsed Laser Deposition

TL;DR

This study uses in-situ x-ray techniques to measure surface diffusivity and coarsening during pulsed laser deposition of SrTiO3, providing new insights into surface dynamics and growth mechanisms.

Contribution

It introduces a method to directly measure diffusivity and surface evolution during PLD, highlighting the roles of nucleation, coarsening, and barriers.

Findings

Measured surface diffusivity during PLD.

Demonstrated the importance of nucleation and coarsening.

Placed bounds on the Ehrlich-Schwoebel barrier.

Abstract

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 reflectivity-based studies, these measurements access both the time- and the 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 intra-layer transport. Our results explicitly limit the possible role of island break-up, demonstrate the key roles played by nucleation and coarsening in PLD, and place an upper bound on the Ehrlich-Schwoebel (ES) barrier for downhill diffusion.