Synthesis and Characterization of Hexagonal Boron Nitride for Neutron Detection Application

Materials containing boron have become important candidates for space radiation detection and shielding because they effectively capture thermal neutrons. This research aims to develop neutron radiation sensing technology using graphene field-effect transistors (gFETs) with hexagonal boron nitride (hBN). To achieve this, we synthesized hBN single crystals in-house via a metal flux method with Ni-Cr. We characterized the hBN using various spectroscopic techniques both before and after neutron irradiation. We observed that neutron irradiation can create specific defects in hBN, indicated by the broadening of Raman peaks after neutron exposure. Then, we transferred the hBN onto a gFET to build the proposed device. It was observed that the device's channel resistance increased proportionally with the total thermal neutron flux. This resistance change results from interactions between the device and alpha particles produced when ¹⁰B captures thermal neutrons. The ability of this device to detect real-time resistance changes during neutron irradiation could significantly enhance astronaut safety by enabling continuous monitoring of neutron exposure.