Nanoscale Phase Identification Using Two-Dimensional Pair Correlation Functions: A Case Study on Hafnium Oxide.

Area of Science:

• Materials Science
• Nanotechnology
• Crystallography

Background:

• Accurate local phase identification is crucial for understanding nanocrystalline material properties.
• Differentiating nanoscale phases in polymorphic and polycrystalline materials is a significant challenge.
• Multiple phases often coexist in thin films, complicating analysis.

Purpose of the Study:

• To develop a robust methodology for nanoscale phase and orientation identification.
• To address the challenge of differentiating coexisting phases in complex nanocrystalline systems.
• To provide a tool applicable to polymorphic materials like hafnium oxide films.

Main Methods:

• Utilized atomically resolved scanning transmission electron microscopy (STEM) imaging.
• Extracted vector pair correlation functions from STEM images.
• Applied the methodology to both simulated and experimental data of HfO2-based films.

Main Results:

• Successfully demonstrated accurate phase and orientation identification at the nanoscale.
• Validated the methodology on HfO2 films exhibiting multiple coexisting phases.
• Achieved reliable results for films with thicknesses between 5 and 20 nm.

Conclusions:

• The developed methodology provides an effective solution for nanoscale phase identification.
• This approach overcomes limitations in analyzing polymorphic materials with complex phase coexistence.
• The technique is extendable to various other polymorphic nanocrystalline systems.