PHYSICS SEMINAR
RADIATION HARDNESS OF GALLIUM NITRIDE
Dr. Anca M. Ionascut Nedelcescu
Physics Department
Bishop’s University
Friday, January 21, 2011
1:30-2:30 p.m.
Nicolls 315
Semiconductor devices employed in space applications are exposed to a variety of energetic particles, which may destroy their function. Consequently, radiation hard materials must be used. The energy required to displace an atom from its lattice site (Ed) is an indication of the material’s radiation hardness. In this work the displacement energy of the gallium atom in gallium nitride (GaN) is measured. GaN thin films and GaN-based double-heterostructured LEDs were irradiated with accelerated proton and electron beams at various energies up to 2 MeV, and different fluences. The change in the optical properties of the irradiated samples allowed the measurement of the threshold energy Eth. Using this quantity the displacement energy in GaN was deduced. The result, Ed = 19 ± 2 eV confirms the radiation hardness of this semiconductor. Based on the experimental results a model of defect creation and recombination as a result of particle irradiation is proposed for GaN.
