Field-Effect Transistor Based on Reduced Graphene Oxide Film with ZnO and Porous Silicon Absorbing Layers for Ionizing Radiation Detection

The graphene field-effect transistor based on the reduced graphene oxide – zinc oxide – porous silicon – silicon substrate sandwich-like structure has been created for ionizing radiation detection. The hybrid structure was obtained as a result of sequential technological processes of photoelectrochemical formation of the nanostructured porous silicon, the electrochemical deposition of zinc oxide, application of a film-forming suspension of reduced graphene oxide nanoparticles, and subsequent drying at room temperature. Dependencies of the drain current on the drain-source voltage and gate voltage of the obtained field-effect transistor were analyzed. An increase in the resistance of the reduced graphene oxide film near the charge neutrality point caused by irradiation with the 226Ra isotope has been found. In addition, a displacement of the charge neutrality point in the direction of a lower gate voltage was observed. It has been established that ionizing radiation has a greater effect on the electronic component of the conductivity of the reduced graphene oxide film than on the hole component. An increase in the sensitivity of the created ionizing radiation detector due to the use of additional zinc oxide and porous silicon absorbing layers was established. Mechanisms of the influence of alpha and beta particles and gamma quanta on the electrical characteristics of the proposed sensor are discussed based on the analysis of the frequency dependences of the internal resistance and electrical capacitance, as well as the capacitance-voltage characteristics of the sandwich-like structure. The obtained results have a high potential to create a new type of small-sized dosimetric devices based on the graphene field-effect transistors using simple and low-cost techniques and materials.