Gallium nitride (GaN) scintillation response to fast neutrons and flash gamma rays and associated broadband photoluminescence

Gallium nitride (GaN), a wide-bandgap semiconductor (3.45 eV), has emerged as a promising material for radiation detection due to its exceptional radiation tolerance, high thermal stability, and ultrafast scintillation response. This study investigates the energy-dependent scintillation response of bulk and thin GaN crystals to fast neutrons and flash gamma rays. Experiments were conducted at the Los Alamos Neutron Science Center using neutron time-of-flight techniques and a fast-gated intensified CCD camera. GaN crystals were exposed to neutron energies ranging from 0.1 to 400 MeV, including the 14.1 MeV relevant to deuterium–tritium fusion. Results indicate a pronounced gamma-induced scintillation signal with prompt full width-at-half-maximum values of 4.27 ns for thin GaN and 3.60 ns for bulk GaN. Rise times were modeled at 90 ps for thin GaN and 662 ps for bulk GaN, confirming rapid response characteristics. Neutron energy-dependent scintillation was observed, and efficiency per millimeter of material was quantified. Broadband photoluminescence observation revealed emission peaks, which are associated with defect states within the crystal structure. Unlike conventional scintillator materials, GaN offers the unique advantage of integration into semiconductor-based circuits, making it highly suitable for radiation-hard diagnostics in fusion power, nuclear reactors, aerospace, and biomedical applications. These findings demonstrate the viability of GaN as a next-generation integrated scintillation material, paving the way for multi-modal, multi-mode-readout diagnostic platforms in high-radiation environments.