Predicting Pulsed-Laser Deposition SrTiO₃ Homoepitaxy Growth Dynamics Using High-Speed Reflection High-Energy...

Area of Science:

• Materials Science
• Surface Science
• Thin Film Deposition

Background:

• Pulsed-laser deposition (PLD) is crucial for complex oxide growth.
• In situ reflection high-energy electron diffraction (RHEED) monitors surface crystallinity during deposition.
• Standard RHEED systems lack the temporal resolution to capture fast growth dynamics.

Purpose of the Study:

• To develop and implement a high-speed RHEED system for capturing in situ growth dynamics at >500 Hz.
• To create an open-source analysis package for extracting surface reconstruction kinetics from high-speed RHEED data.
• To investigate the influence of substrate surface properties on growth dynamics in PLD.

Main Methods:

• Implementation of a high-speed RHEED platform capable of >500 Hz acquisition.
• Development of an open-source software package for analyzing RHEED data by fitting diffraction spots to 2D Gaussians.
• Homoepitaxial growth of (001)-oriented SrTiO₃ as a model system.
• Analysis of single-pulse surface reconstruction kinetics using exponential fitting.

Main Results:

• High-speed RHEED successfully captured in situ growth dynamics previously obscured by slower systems.
• Characteristic decay times of diffraction intensity were correlated with substrate step width and surface termination.
• Diffraction intensity decayed on TiO₂-terminated surfaces and stabilized on SrO- or mixed-terminated surfaces.
• Adatom deposition kinetics were found to be influenced by the density of bonding sites and step width.

Conclusions:

• Increased temporal resolution in RHEED provides new insights into PLD growth mechanisms.
• Substrate surface termination and step morphology significantly impact thin film growth kinetics.
• The developed platform enables data-driven analysis and autonomous control for enhanced PLD processes.