Ionizing Radiation Detection Using the Field Effect Transistor Based on Reduced Graphene Oxide

In this study, the graphene field-effect transistor (FET) has been created by depositing a film-forming suspension of reduced graphene oxide (RGO) on the silicon substrate with a SiO2 layer and air-drying at room temperature. The possibility of using the obtained FET for ionizing radiation detection was investigated. The electrical characteristics of the radiation sensor based on the RGO film were studied in modes of direct current and alternating current. The dependencies of the drain current and the resistance of the RGO film on the gate voltage of the obtained FET were analyzed. Linear sections on the dependence of the drain current on the gate voltage, the positions of which are determined by the sign of the drain-source voltage, were detected. A decrease in the conductivity of the FET based on the RGO film near the point of charge neutrality due to irradiation from the 226Ra isotope was established. An increase in resistance and a decrease in capacitance of the investigated FET have been found in the frequency range of 25 Hz – 1 MHz caused by the joint action of alpha and beta particles and gamma quanta. A linear dependence of the electrical characteristics of the proposed sensor on the adsorbed dose determined by the irradiation duration was discovered. Possible mechanisms of the ionizing radiation influence on the conductivity of the obtained structure based on the RGO film are considered. The generation of electron-hole pairs in the silicon substrate and the formation of radiation defects in the insulator layer are probably the main factors affecting the electrical characteristics of the RGO-based FET under the action of ionizing radiation. The obtained results expand the perspective of using graphene FETs to create a new type of radiation detectors and dosimetric devices.