Impact of radiation-induced point defects on thermal carrier decay processes in GaAs

The relative rate of optical to thermal carrier decay plays a critical role in the performance of optoelectronic devices, and radiation-induced point defects can significantly affect this ratio. To deepen the understanding of how radiation affects the performance of optoelectronic media, the thermal decay rates for each of the six possible point defects in a classical optoelectronic material, GaAs, are evaluated using a first-principles-based theory of multi-phonon emission. The determined rates reflect the propensity of electrons or holes to couple with particular defect vibrations, illuminating which material defects are most detrimental. When combined with the optical decay rates and dielectric function, the thermal decay rates provide a microscopic understanding of how radiation exposure upsets the intended carrier relaxation pathway. These findings could aid in the computational design of radiation hard optoelectronic systems, or with forging new measures to suppress the creation of defects most detrimental to optoelectronic performance.