Band Engineering of Multiple‐Quantum‐Well Scintillators by Low‐Energy Electron‐Beam Irradiation

Abstract High‐performance scintillators are essential for developing the emerging field of nano‐scintillation. In this field, scintillation can be enhanced or controlled by nanophotonic structures, making it valuable for medical imaging, radiative detection, and high‐energy physics. Multiple‐quantum‐well structures based on group III‐nitride semiconductors are well‐known scintillators for flexibility in tuning the emission wavelength. However, they suffer from low radiative efficiency due to the strong quantum‐confined Stark effect and high defect density. In this work, a nano‐scintillator prepared using low‐energy electron beam irradiation (LEEBI) for band engineering is demonstrated. A two‐order‐of‐magnitude increase is achieved in scintillation intensity without any shift in the emission peak. Furthermore, the carrier lifetime is counter‐intuitively ten times longer. Using simulations and self‐consistent calculations, the results and underlying mechanisms are analyzed. The prominent enhancement of scintillation efficiency suggests new strategies for establishing ultra‐low threshold electron‐beam‐pumped lasers. These findings will not only offer a resolution to the long‐standing contradictions surrounding LEEBI, but also push the boundaries of nano‐scintillation.