Oxygen is the most common unintentional impurity found in GaN. We study the interaction between substitutional oxygen (ON) and the gallium vacancy (VGa) to form a point defect complex in GaN. The formation energy of the gallium vacancy is largely reduced in n-type GaN by complexing with oxygen, while thermodynamic and optical transition levels remain within the bandgap. We study the spectroscopy of this complex using a hybrid quantum-mechanical molecular-mechanical embedded-cluster approach. We reveal how a single defect center can be responsible for multiband luminescence, including possible contributions to the ubiquitous yellow luminescence signatures observed in n-type GaN, owing to the coexistence of diffuse (extended) and compact (localized) holes.
Bibliographical noteFunding Information:
This project was supported by the EU Environment and PECO Program, partly through the Swedish Medical Council and the National Environmental Protection Board, by the Swedish Cancer Fund and by the Belgian Incentive Program for Health Hazards, funded by the Services of the Prime Minister and by grant No. 3157-3 IGA, Czech Ministry of Health.
© 2018 Author(s).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)