Date

2016

Document Type

Dissertation

Degree

Doctor of Philosophy

Department

Physics

First Adviser

Dierolf, Volkmar

Other advisers/committee members

Stavola, Michael; DeLeo, Gary; Biaggio, Ivan; Kumar, Sushil

Abstract

Europium doped gallium nitride (GaN:Eu) is an active area of research as it has been recognized as a candidate for the red-emitting active layer in nitride-based technologies. This dissertation reports on the optical influences of defects on Eu ions in GaN:Eu. A comprehensive study was completed to research materials incorporating a variety of structures, growth parameters, and co-dopants. Analyzing traditional samples provided new insight into typical incorporation environments. Materials incorporating quantum well structures, an oxygen-free Eu source, and co-doping with oxygen highlighted the importance of the aforementioned dopant, especially in the development of minority sites.To better comprehend the excitation energy transfer from the excited GaN host to the Eu ion, experiments were designed to complete power dependent measurements and explore the saturation behavior of the Eu emission in the GaN material. Further, we determined how various growth parameters modified site formations and measured the optical accessibility of the ions within the GaN host. With these results, we derived a theoretical model for the saturation behavior of Eu ion emission.In other avenues of this work, the role of charged defects on the structural and luminescence characteristics of Eu ions was explored. A novel multiple excitation emission spectroscopy (MEES) technique was designed and implemented to explore the optical properties of the ions under various temperatures and excitation conditions. A model was developed for the structural properties of one of the minority Eu centers and its relationship, facilitated by an acceptor defect, with one of the most efficiently excited sites in GaN:Eu.

Available for download on Saturday, October 28, 2017

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