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Nuclear Engineering

Air Force Institute of Technology

Theses and Dissertations

Irradiation

Publication Year

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Full-Text Articles in Engineering

Temperature Dependent Current-Voltage Measurements Of Neutron Irradiated Al0.27Ga0.73N/Gan Modulation Doped Field Effect Transistors, Troy A. Uhlman Mar 2005

Temperature Dependent Current-Voltage Measurements Of Neutron Irradiated Al0.27Ga0.73N/Gan Modulation Doped Field Effect Transistors, Troy A. Uhlman

Theses and Dissertations

In this research, the first ever neutron irradiation study of AlGaN/GaN MODFETs was conducted. Devices irradiated to a total 1 MeV Eq (Si) neutron fluence of 1.2x1016 n/sq cm demonstrated the temperature dependence of irradiation and annealing. Devices irradiated at 80 K exhibited significant persistent electrical degradation at only 5.4 rad (Si), whereas those irradiated at elevated temperatures exhibit transient increases in gate and drain current up to 400 krad (Si). I-V measurements indicate substantial radiation-induced increased gate and drain currents occur only at low-temperature irradiations. The introduction of a high-density of donor defects is hypothesized as the primary …


Electron Paramagnetic Resonance Spectroscopy And Hall Effect Studies Of The Effects Of Low Energy Electron Energy On Gallium Nitride (Gan), Kevin D. Greene Sep 2003

Electron Paramagnetic Resonance Spectroscopy And Hall Effect Studies Of The Effects Of Low Energy Electron Energy On Gallium Nitride (Gan), Kevin D. Greene

Theses and Dissertations

The nature of native donors in GaN, types and interactions of radiation-induced defects, and damage creation coefficients for 1.0 MeV electron irradiation have been ascertained by the concerted application of electron paramagnetic resonance spectroscopy and Hall effect measurements to virgin and electron-irradiated GaN epilayers. Samples produced via molecular beam epitaxy and hydride vapor phase epitaxy, both silicon doped and nominally undoped, were subjected to Van de Graff generator produced monoenergtic electron beams with total fluences of 1016- 1018 electrons/cm2. Nitrogen vacancies are rejected as a possible cause of n-type conductivity in nominally undoped GaN due …