Nanocomposites and nanomaterials

Composites based on silicon and carbon nanostructures for ionizing radiation sensing
I.B. Olenych1, Yu.Yu. Horbenko2, L.S. Monastyrskii1, O.I. Aksimentyeva2, O.S. Dzendzeliuk1, B.S. Sokolovskii1
1 Electronics and Computer Technologies Department, Ivan Franko National University of Lviv, 50 Dragomanov Str., Lviv-79005, Ukraine
E-mail: iolenych@gmail.com
2 Chemistry Department, Ivan Franko National University of Lviv, 6 Kyrylo and Mefodiy Str., Lviv-79005, Ukraine 

The search for new functional materials with predictable properties is at the forefront of R&D in nanoelectronics. In particular, composite materials that are a collection of related to each other nanoparticles are actively studied. Particular attention is paid to nanosystems based on graphene and porous silicon nanostructures due to their unique properties. The significant specific area of the porous silicon, high carrier mobility and mechanical strength of the graphene, as well as significant sensitivity of electrical conductivity of silicon and carbon nanostructures to adsorbed molecules and local electric fields, make nanocomposites based on them strong candidates for sensor development [1, 2]. 
In this work, PS–graphene hybrid structures were created and their electrical properties in the AC regime under ionizing radiation from the 226Ra source were studied. A decrease in electrical resistance and capacitance of the PS–graphene structures with increasing frequency from 25 Hz to 1 MHz was established based on the measurement of frequency dependences of the impedance. We have found that the obtained hybrid structures show a decrease in resistance and an increase in capacitance due to the combined action of α-, β-, and γ-radiation. Radiation-induced charge in the PS causes a change in the local electric field and, as a consequence, a change in the electrical characteristics of graphene. A study of the ionizing radiation effect on electrical parameters of the PS–graphene nanocomposites opens the way to creating new types of ionizing radiation detectors. 

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