- and Gamma-Induced Displacement Damage Effects in Indium Phosphide Semiconductor Devices

Usually the effects of particle radiation on solar cells that are flown in a hostile space radiation environment, such as the Van Allen belts, are often simulated on the ground using experimental results obtained with 1 MeV electrons. With the increasing cost and the continual decline in availability of electron accelerators at which to perform these tests, the need for an alternative radiation testing method is desirable. This dissertation discusses the use of Co ^{60} gamma ray irradiation as a way of producing displacement damage effects in semiconductor devices, and how these effects can be correlated with the effect of 1 MeV electrons. This correlation can be calculated from first principles. For the effect of the gamma rays, knowledge of the primary Compton electron and photoelectron differential spectra, the total stopping power, and the nonionizing energy loss are required in order to calculate the equivalent 1 MeV electron fluence. The nonionizing energy loss is calculated using differential electron scattering cross sections, recoil energies, and the partition of the energy into displacement and ionization terms. The effects of both 1 MeV electron and Co^{60} gamma ray irradiations on the photovoltaic parameters on both n^{+}p and p ^{+}n InP solar cells are discussed as an example of the method and are shown to be in good agreement with the theory.