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Epitaxial multilayer heterostructures of ScxAl1−xN/GaN with Sc contents x = 0.11–0.45 are found to exhibit significant differences in structural quality, chemical impurity levels, and electronic properties depending on the starting Sc source impurity levels. A higher purity source leads to a 2–3 orders of magnitude reduction in the carbon, oxygen, and fluorine unintentional doping densities in MBE-grown ScxAl1−xN/GaN multilayers. Electrical measurements of ScxAl1−xN/n+GaN single heterostructure barriers show a 5–7 orders of magnitude reduction in the electrical leakage for films grown with a higher purity Sc source at most Sc contents. The measured chemical and electrical properties of epitaxial ScxAl1−xN highlight the importance of the starting Sc source material purity for epitaxial device applications that need these highly piezoelectric and/or ferroelectric transition-metal nitride alloys.
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Onset of tetrahedral interstitial formation in GaAsN alloys
N incorporation mechanisms in GaAs1−xNx alloys are probed using combined experimental and computational Rutherford backscattering spectrometry and nuclear reaction analysis angular yield scans. For xN < 0.025, in addition to substitutional nitrogen, NAs, (N-N)As, and (N-As)As split-interstitials are observed. However, for xN ≥ 0.025, evidence for N tetrahedral interstitials, Ntetra, emerges. We propose a mechanism for stabilization of Ntetra in which the elastic interaction between Ntetra and NAs is induced by the opposite signs of their misfit volumes. This work opens opportunities for exploring the formation of Ntetra and its influence on the properties of a variety of highly mismatched alloys.
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- PAR ID:
- 10511978
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 124
- Issue:
- 16
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0192454
