In Situ Composition and Thickness Monitoring during (Bi_xIn_1‑x)₂Se₃ Thin Film Growth: toward Automated Synthesis...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Ternary compounds like (Bi_xIn_1-x)₂Se₃ are promising for quantum and spintronic applications.
• Precise control over material composition and thickness during growth is essential for device performance.
• Existing characterization methods often require ex situ analysis, interrupting the growth process.

Purpose of the Study:

• To develop a method for real-time monitoring of ternary compound growth parameters.
• To enable immediate determination of composition and thickness during molecular beam epitaxy (MBE).
• To establish a transferable model for diverse MBE systems and monitor growth kinetics.

Main Methods:

• Coupling in situ spectroscopic ellipsometry with an MBE growth chamber.
• Growth and characterization of (Bi_xIn_1-x)₂Se₃ films (x=0 to 1) using X-ray reflectivity, XPS, and RBS.
• Fitting ellipsometry spectra with Kramers-Kronig-consistent oscillators to derive composition-dependent dielectric functions and create a material file.

Main Results:

• A material file was created, enabling immediate determination of Bi content and thickness for (Bi_xIn_1-x)₂Se₃ films at any growth stage.
• The developed model demonstrated universality and transferability across different MBE growth systems.
• For the first time, sticking and desorption coefficients for Bi₂Se₃ thin films were monitored in operando.

Conclusions:

• The integrated in situ spectroscopic ellipsometry-MBE system provides real-time feedback for precise ternary compound fabrication.
• This approach significantly enhances reproducibility and control in device fabrication for quantum and spintronic applications.
• The findings advance the understanding of thin film growth kinetics and contribute to addressing future electronic performance demands.