Nanocomposites and nanomaterials

Electrical and sensory properties of silicon – graphene nanosystems
I.B. Olenych, O.I. Aksimentyeva, Yu.Yu. Horbenko
Ivan Franko National University of Lviv, 50 Dragomanov Str., Lviv-79005, Ukraine. E-mail: iolenych@gmail.com

The development of new generation of electronic devices is associated with nanostructured materials. Hybrid nanomaterials are an important research field. The combination of silicon nanoparticles and two-dimensional carbon material (e.g. graphene and graphene oxide) is especially promising for electronics. In particular, graphene coating is used to increase the conductivity of photoelectric transducers [1] and to improve electrochemical characteristics of electrode materials for supercapacitors and lithium-ion batteries [2]. In addition, ultra-high specific surface area of graphene and silicon nanostructures causes high sensitivity of nanomaterials to the adsorption of gas molecules [3]. However, implementation of the nanosystems based on silicon and graphene in sensor devices requires systematic studies of charge transfer processes under the influence of external factors. 
In this work the silicon – graphene nanosystems were manufactured by coating silicon nanostructures with reduced graphene oxide in order to study their electrical and gas sensing properties. The charge transport in obtained nanocomposites was studied in DC and AC modes. It was found that the electrical characteristics of the silicon – graphene nanosystems were strongly dependent on the surrounding atmosphere. In particular, the adsorption of ammonia and ethanol molecules causes a decrease in resistance and an increase in the capacity of nanomaterial. To estimate the sensory properties of the silicon – graphene nanosystem its adsorption sensitivity to ammonia and ethanol action was analyzed. 

1.	Olenych I.B., Aksimentyeva O.I., Monastyrskii L.S., Horbenko Yu.Yu., Partyka M.V. Electrical and Photoelectrical Properties of Reduced Graphene Oxide – Porous Silicon Nanostructures // Nanoscale Res. Lett.-2017.-12.-272. 
2.	Cen Y., Sisson R.D., Qin Q., Liang J. Current Progress of Si/Graphene Nanocomposites for Lithium-Ion Batteries // Journal of Carbon Research.-2018.-4.-18. 
3.	Olenych I.B., Monastyrskii L.S., Aksimentyeva O.I., Orovcík L., Salamakha M.Y. Charge Transport in Porous Silicon/Graphene-Based Nanostructures // Molec. Cryst. Liq. Cryst.-2018.-673.-32.