Self-driven beta-radiation detection through a graphene/water/silicon heterostructure

Abstract

Large-volume neutrino observatories, exemplified by IceCube, exploit Cherenkov light generated by neutrino-induced charged particles in Antarctic ice, highlighting the potential of water-based media for high-energy particle detection. In $β$-decay, a neutron converts into a proton via the weak interaction, emitting an electron and an electron antineutrino. The electron constitutes the beta radiation detected in this work, while the accompanying antineutrino motivates future extensions toward neutrino detection. Here we demonstrate a complementary electrical transduction strategy using a graphene/water/silicon heterostructure that generates reversible current transients under beta irradiation at zero applied bias. Energetic electrons deposit energy in silicon, producing nonequilibrium carriers that perturb the semiconductor surface potential and electric displacement across the adjacent aqueous interface. The resulting redistribution of interfacial water polarization drives a transient compensation current, whereas carrier relaxation restores the initial polarization state and generates an opposite-polarity recovery signal. The complete irradiation-detector-electrometer system exhibits exponential rise and recovery time constants of approximately 1.0 and 3.6 ms, respectively. The response is strongly regulated by water-layer thickness and ionic composition, and the 17 beam pulses of a programmed 1 s sequence at 17 Hz are resolved individually. Integration with Ce:YAG further introduces a scintillation-mediated excitation pathway. These findings establish interfacial water polarization as a tunable, zero-bias electrical transduction mechanism for time-resolved beta-radiation monitoring and motivate future investigations of higher-energy charged particles and secondary particles relevant to neutrino detection.