Defect Control Strategies for Al1-xGdxN Alloys: Article No. 155101

Cheng-Wei Lee, Naseem Ud Din, Keisuke Yazawa, William Nemeth, Rebecca Smaha, Nancy Haegel, Prashun Gorai

Research output: Contribution to journalArticlepeer-review


Tetrahedrally bonded III-N and related alloys are useful for a wide range of applications from optoelectronics to dielectric electromechanics. Heterostructural AlN-based alloys offer unique properties for piezoelectrics, ferroelectrics, and other emerging applications. Atomic-scale point defects and impurities can strongly affect the functional properties of materials, and therefore, it is crucial to understand the nature of these defects and the mechanisms through which their concentrations may be controlled in AlN-based alloys. In this study, we employ density functional theory with alloy modeling and point defect calculations to investigate native point defects and unintentional impurities in Al1-xGdxN alloys. Among the native defects that introduce deep midgap states, nitrogen vacancies (VN) are predicted to be in the highest concentration, especially under N-poor growth conditions. We predict and experimentally demonstrate that VN formation can be suppressed in thin films through growth in N-rich environments. We also find that Al1-xGdxN alloys are prone to high levels of unintentional O incorporation, which indirectly leads to even higher concentrations of deep defects. Growth under N-rich/reducing conditions is predicted to minimize and partially alleviate the effects of O incorporation. The results of this study provide valuable insights into the defect behavior in wurtzite nitride-based alloys, which can guide their design and optimization for various applications.
Original languageAmerican English
Number of pages11
JournalJournal of Applied Physics
Issue number15
StatePublished - 2024

NREL Publication Number

  • NREL/JA-5K00-86356


  • alloys
  • crystallographic defects
  • density functional theory
  • ferroelectric materials
  • thin film growth


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