Synergistic roles of electronic and nuclear energy deposition: From defect generation to performance degradation in heavy-ion-irradiated CdZnTe crystals

Understanding the irradiation damage of cadmium zinc telluride (CdZnTe, CZT) crystals and its effect on photoelectric properties is crucial for their reliable use in radiation detection. This study examines the combined influence of electronic (S_e) and nuclear (S_n) energy loss on the microstructure, current transport, and carrier characteristics of CZT using 516 MeV and 1.5 MeV Xe ion irradiations. Results indicate that the synergistic S_e/S_n effect critically influences defect evolution pathways, leading to divergent microstructures. High S_e favors dislocation loops through thermal-spike-enhanced kinetics, whereas high S_n, by exacerbating lattice damage, promotes stacking faults and the evolution of loops into large-scale dislocation lines. Defect levels are deeper and the concentration of defects is larger after 516 MeV irradiation than after 1.5 MeV. Leakage current mechanisms are dominated by Schottky emission (SE) combined with the Poole-Frenkel (PF) effect for 516 MeV Xe ions, and by Fowler-Nordheim (F-N) tunneling coupled with PF effect for 1.5 MeV Xe ions. Carrier transport and γ-ray detection performance degrade more severely under 516 MeV irradiation, likely because of its broader damage layer and deeper defect levels. These findings provide a theoretical basis for understanding radiation damage mechanisms and performance recovery in CZT, offering valuable insights for radiation protection in spaceborne equipment.