Optical Science and Engineering ETDs

Publication Date

Summer 7-2022

Abstract

III-nitride material (GaN) shows a lot of potential for next-generation power electronics. This material is advantageous due to its wide bandgap, high electron mobility, high thermal and mechanical stability, small form factor, and higher radiation tolerance. The higher radiation tolerance makes the GaN-based devices more attractive for harsh-environment applications, like aerospace, nuclear reactor, and fusion facilities, particle accelerators, and post-detonation environments applications.

GaN due to its unique crystal structure can be grown in different orientations and can provide specific advantages in electronic and optoelectronic devices. While the Ga-polar orientation of GaN has been widely investigated for its proprieties, there are still rooms to study other orientations. The optical and electrical characteristics of GaN-based diodes are studied on Ga-polar and N-polar orientation in this thesis. The opposite polarity, different defect, and impurity incorporation in these two orientation results in different behaviors after gamma and neutron irradiation of these devices. Current-voltage, circular transfer line method, capacitance-voltage, and RF measurements are mainly used to study the characteristics of the diodes due to gamma and neutron irradiation. The study shows that Ga-polar and N-polar GaN Schottky diodes exhibit significant and different changes in electrical behavior after both gamma and neutron irradiation. The origin of the different behaviors is attributed to the fundamental differences between the Ga-polar and N-polar orientations, such as their opposite polarization and differences in impurity incorporation, defect types, and surface reactivity.

Degree Name

Optical Science and Engineering

Level of Degree

Doctoral

Department Name

Optical Science and Engineering

First Committee Member (Chair)

Daniel Feezell

Second Committee Member

Ganesh Balakrishnan

Third Committee Member

Payman Zarkesh-Ha

Fourth Committee Member

Azaree Lintereur

Keywords

Gallium Nitride, Diode, Gamma, Neutron, Radiation tolerance, RF measurement

Sponsors

DTRA

Document Type

Dissertation

Language

English

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