Effect of TiO2 nanoparticles on electrical properties of chemical vapor deposition grown single layer graphene

Abstract

Modification of charge carriers is essential for better performance of electronic and optoelectronic devices based on graphene. In this article, we study the effect of different concentrations of titanium dioxide (TiO2) nanoparticles (NPs) on chemical vapor deposition (CVD) grown graphene by using Raman spectroscopy and electrical charge transport measurements. Large-area and single-layer graphene (SLG) film were grown on copper (Cu) foil by the CVD process and grown films were transferred onto the Si/SiO2 substrate for electrical measurements and other characterizations. The Raman spectra and electrical charge transport measurements show that TiO2 NPs change the electronic properties as well as the structure of the CVD-grown graphene. The drain current versus back gate voltage measurements revealed that TiO2 NPs imposed p-type doping in CVD-grown SLG. In Raman spectra, peak frequencies shifts were analyzed before and after the doping of TiO2 NPs on CVD graphene. The shifting of 2D peaks positions towards higher wavenumber also indicates the p-type doping in graphene by TiO2 NPs. We believe that our study may be useful to understand the charge transport phenomena in TiO2 doped graphene-based electronics devices.