<i>In situ</i> transmission electron microscopy observation of N ion radiation damage in the GaN material at high temperature

Abstract

This study employs in situ transmission electron microscopy (TEM) to investigate the dynamic evolution of radiation-induced defects in gallium nitride (GaN) under high temperature (800 °C). The results demonstrate that defect cluster size increases progressively with irradiation dose (up to 2.48 displacements per atom, dpa), while cluster density exhibits a non-monotonic trend, peaking at intermediate doses (0.31–0.62 dpa) before declining due to coalescence of smaller clusters. Aberration-corrected scanning TEM reveals that irradiation generates dislocations, stacking faults, and cavities. Besides, N2 bubbles nucleate even at ultralow doses (0.02 dpa), driven by interstitial N aggregation and vacancy capture. Despite significant radiation damage, GaN maintains its crystalline structure without amorphization at high doses. Besides, there is negligible aggregation of defects around intrinsic dislocations—a behavior attributed to the high migration energy barriers of vacancies and interstitials in GaN. These findings elucidate the intrinsic radiation resistance mechanisms of GaN through atomic-level defect dynamics, providing critical guidance for designing next-generation radiation-tolerant power electronics and radiation detectors in extreme environments such as nuclear reactors and space applications.