Related Experiment Video
Updated: Jul 14, 2026
14:16
Fabrication of Schottky Diodes on Zn-polar BeMgZnO/ZnO Heterostructure Grown by Plasma-assisted Molecular Beam Epitaxy
Published on: October 23, 2018
Decoupling composition and band gap in κ-Ga2O3 heterostructures via STEM-EELS.
Annett Thøgersen1, Georg Muntingh2, Lasse Vines3
1SINTEF Industry, Materials Physics, Forskningsveien 1, 0373 Oslo, Norway.
Ultramicroscopy
|July 12, 2026
Summary
Strain significantly reduces the band gap in ultrathin gallium oxide multilayers, a finding enabled by advanced microscopy. This study quantizes band-gap variations, crucial for understanding complex oxide heterostructures.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Accurate band-gap measurement in oxide heterostructures is difficult due to probe delocalization and spectral overlap.
- Understanding the interplay between strain and composition is crucial for tailoring electronic properties.
Purpose of the Study:
- To develop and apply a method for high-resolution band-gap mapping in ultrathin κ-Ga2O3 multilayers.
- To decouple the effects of strain, composition, and measurement artifacts on band-gap variations.
Main Methods:
- Monochromated, probe-corrected scanning transmission electron microscopy with low-loss electron energy-loss spectroscopy (STEM-EELS).
- A transparent Python workflow for band-gap fitting and data analysis.
- Geometrical phase analysis (GPA) for strain mapping and plasmon tracking for composition analysis.
Main Results:
- Quantified local band-gap variations in ultrathin κ-Ga2O3 multilayers, resolving transitions down to a few nanometers.
- Identified a significant band-gap reduction (5.08 to 4.28 eV) in heterostructures grown on ITO, attributed to compressive strain.
- Demonstrated that ZnO-templated multilayers exhibit relaxed interfaces and band gaps consistent with composition.
Conclusions:
- Physically informed VEELS analysis reliably decouples strain, composition, and measurement artifacts.
- STEM-EELS is established as a robust tool for nanoscale electronic-structure characterization in complex oxide heterostructures.
- Strain engineering is a key factor in controlling band-gap properties in oxide multilayers.
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