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Identification of the nitrogen split interstitial (N-N)(N) in GaN
H J von Bardeleben1, J L Cantin, U Gerstmann
1INSP, Université Pierre et Marie Curie, UMR 7588 au CNRS 4 place Jussieu, 75005 Paris, France. vonbarde@insp.jussieu.fr
Physical Review Letters
|December 11, 2012
Summary
Researchers identified a nitrogen interstitial defect in gallium nitride (GaN) using multiple spectroscopy techniques. This defect is unstable, transforms into a split interstitial, and anneals out at 400 °C.
Area of Science:
- Materials Science
- Solid-State Physics
- Defect Engineering
Background:
- Gallium nitride (GaN) is a crucial semiconductor for optoelectronic and high-power applications.
- Understanding point defects is essential for optimizing GaN material properties and device performance.
- Nitrogen interstitials are common defects in irradiated GaN but their configurations and behavior are not fully understood.
Purpose of the Study:
- To identify and characterize the nitrogen interstitial defect in GaN.
- To investigate the transformation pathways and thermal stability of this defect.
- To correlate defect behavior with Fermi level pinning and observed nitrogen vacancies.
Main Methods:
- Electron Paramagnetic Resonance (EPR) spectroscopy for defect identification.
- Density Functional Theory (DFT) for theoretical modeling of defect structures and energies.
- Positron Annihilation Spectroscopy (PAS) for vacancy detection.
Main Results:
- The isolated nitrogen interstitial defect in GaN was identified.
- The defect is unstable and transforms into a split interstitial configuration, (N-N)(N).
- This defect pins the Fermi level at E(C)-1.0 eV under high particle irradiation fluences and anneals out at 400 °C.
Conclusions:
- The study elucidates the nature and behavior of nitrogen interstitial defects in GaN.
- The findings provide insights into defect-induced Fermi level pinning and annealing kinetics.
- The associated nitrogen vacancy is transient, observed only during the early stages of irradiation.
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