Effects of 10Â MeV electron irradiation on the characteristics of gallium-nitride-based pin alpha-particle detectors

GaN-based pin alpha-particle detectors grown on sapphire substrates have been subjected to 10 MeV electron irradiation over a cumulative dose range of 0 to 200 kGy. The pre- and post-irradiation detectors have been characterized with current-voltage and capacitance-voltage measurements, charge collection efficiency (CCE), and alpha-particle pulse-height spectroscopy. The results show that the performance of the detectors underwent significant changes due to enhanced carrier-hopping conductivity through defect states and deep-level traps in the space-charge region induced by the 10 MeV electron irradiation. Such detectors can be used for alpha detection with confidence in an environment of background high energy electrons, up to a dose of about 200 kGy, and the response can degrade rapidly if the dose exceeds 200 kGy. In this work, the maximum CCE was achieved in a detectors irradiated with a cumulative dose of 100 kGy.