Understanding the Nature of Crystallographic Bonds by Establishing the Correlation between Ion-Pair Chemistry and Their Separation in Detector Space.

The occurrence of multi-hit events and the separation distance between multi-hit ion pairs field evaporated from III-nitride semiconductors can potentially provide insights on neighboring chemistry, crystal structure, and field conditions. In this work, we quantify the range of variation in major III-N and III-III ion-pair separation to establish correlations with bulk composition, growth method, and ion-pair chemistry. The analysis of ion-pair separation along the AlGaN/GaN heterostructure system allows for comparison of Ga-N and Ga-Ga ion-pair separation between events evaporated from pure GaN and Al0.

Correlation of Multiplicity and Chemistry in Al GaN Heterostructure via Atom Probe Tomography.

In this work, the correlation between composition and relative evaporation field was investigated by tracking the statistics of multi-hit detector events in atom probe tomography (APT). This approach is applied systematically to a GaN-based nitride heterostructure with five AlxGa1-xN layers of varying Al composition. The relative field evaporation and the percentage of multi-hit events were found to increase with higher Al concentration.