Pressure-driven selective sublimation and electron-beam-induced sputtering during high vacuum heating observed by
Kyu-Jin Jo1, Jin-Su Oh1, Cheol-Woong Yang1
1School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Micron (Oxford, England : 1993)
|April 15, 2026
Summary
Investigating germanium telluride (GeTe) using in situ heating transmission electron microscopy (TEM) revealed artifacts from electron beams and vacuum. Minimizing beam current and controlling temperature are crucial for accurate microstructural analysis.
Area of Science:
- Materials Science
- Nanotechnology
- Solid State Physics
Background:
- In situ heating transmission electron microscopy (TEM) allows real-time observation of material changes.
- Electron beam irradiation and high vacuum can cause artifacts, complicating interpretation of TEM data.
Purpose of the Study:
- To systematically investigate electron beam and vacuum effects on germanium telluride (GeTe) during in situ heating TEM.
- To identify conditions for reliable microstructural analysis of GeTe.
Main Methods:
- Ex situ heat treatment of bulk GeTe under air, argon, and high vacuum (∼10⁻⁵ Pa).
- In situ heating TEM (CTEM and STEM) of GeTe thin foils under varying electron beam conditions.
- Analysis of microstructural evolution, including oxidation, interdiffusion, sublimation, and sputtering.
Main Results:
- Bulk GeTe showed oxidation (air), Ge-Te interdiffusion (argon), and Te sublimation (high vacuum) at 450 °C.
- In situ CTEM revealed GeTe sputtering and hole formation at 300 °C (80-200 kV).
- Sputtering was reduced with low probe current in STEM; however, Te sublimation and Ge agglomeration occurred at 325 °C, forming Ge nanocrystals.
Conclusions:
- Electron beam sputtering and element sublimation are significant artifacts in in situ heating TEM of GeTe.
- Minimizing beam current density and selecting temperatures below the lowest sublimation point of constituent elements are essential for accurate GeTe analysis.
- Understanding these artifacts is critical for reliable interpretation of TEM studies on phase-change materials.
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