Measurements of surface diffusivity and coarsening during pulsed laser deposition

Area of Science:

• Materials Science
• Surface Science
• Thin Film Growth

Background:

• Pulsed laser deposition (PLD) is a key technique for thin film fabrication.
• Understanding surface morphology evolution during growth is crucial for controlling film properties.
• Previous studies relied on reflectivity alone, limiting insights into dynamic processes.

Purpose of the Study:

• To investigate the surface morphology evolution during homoepitaxial SrTiO(3) 001 growth by PLD.
• To directly measure inter- and intralayer transport diffusivity.
• To elucidate the roles of nucleation, coarsening, and island breakup in PLD.

Main Methods:

• In situ X-ray specular reflectivity and surface diffuse X-ray scattering.
• Simultaneous measurement of surface morphology dynamics across multiple time and length scales.
• Analysis of diffusion processes governing surface evolution.

Main Results:

• Direct measurement of inter- and intralayer diffusion coefficients.
• Demonstration that island breakup plays a limited role in PLD.
• Identification of nucleation and coarsening as dominant processes.
• Establishment of an upper bound for the Ehrlich-Schwoebel barrier.

Conclusions:

• Combined X-ray scattering techniques provide unprecedented insight into PLD dynamics.
• Nucleation and coarsening are critical factors in achieving high-quality SrTiO(3) films.
• The Ehrlich-Schwoebel barrier is constrained, impacting future growth models.