To explore more accurate and reliable space-based nuclear explosion detection technologies, this paper employs the finite element method and technology computer-aided design to study the detection mechanism, operational characteristics, and performance advantages of GaN and 4H-SiC neutron radiation detectors. The detector structure and irradiation models were established and validated against existing data. The current density and capacitance-voltage curves of GaN and SiC Schottky diodes were compared, and the transient response and charge collection efficiency of the devices under various reverse-bias voltages post irradiation were obtained.

The results show that the peak transient current increases with the bias voltage. At the Schottky side, the collected charge is comprised of both holes and electrons, while at the ohmic side, it consists only of electrons. The collected charge mainly originates from the drift and diffusion carriers in the depletion, funnel, and diffusion regions, with the depletion region drift charge being the most significant. GaN detectors, compared to SiC, exhibit lower power consumption and higher charge collection efficiency, underscoring their potential in radiation detector development.