Correlative local assessment of single layer graphene/beta-Ga2O3 microwire-based photodetectors: the role of defects

We aim to study, with nanoscale spatial resolution, the X-ray beam induced current (XBIC) in graphene/β-Ga₂O₃ microwire (μW) heterojunction devices, combined with X-ray excited optical luminescence (XEOL) and X-ray absorption near-edge structure (XANES). These devices show highly efficient UVC and X-ray photodetection, with self-powered operation and faster response and higher responsivity than Pt/β-Ga₂O₃ μW Schottky devices. A key factor governing their behaviour is the presence of point defects, such as Ga and O vacancies, which act as carrier traps. Luminescence techniques like XEOL provide defect signatures, while the high spatial resolution of ID16B enables correlation of XBIC and XEOL
signals across different μW regions (contacted vs. non-contacted). Complementary XANES will further reveal changes in the Ga chemical environment. These measurements will clarify the role of defects in charge transport and photodetection, i.e. the physical mechanisms, and guide device optimization.