Tailoring of electrical properties of TiO2 decorated CVD grown single-layer graphene by HNO3 molecular doping

Abstract Control of carrier density and shifting of Fermi level provides an approach to tune the physical properties of two-dimensional graphene. Here, we report the modulation in electrical properties of chemical vapor deposition (CVD) grown single-layer graphene (SLG) and titanium dioxide (TiO2) nanoparticles (NPs) decorated SLG by nitric acid (HNO3) molecules. The Raman spectroscopy and charge transport measurement confirmed HNO3 treatment leads to p-type doping in both i.e. pristine graphene and TiO2 coated SLG. The shift and relative intensity ratio of G and 2D peaks are analyzed after HNO3 treatment. For HNO3 doped without and with TiO2 NPs coated CVD grown SLG, a substantial Dirac point shift is observed in transfer characteristic, reveal p-type doping of CVD grown SLG through charge transfer and HNO3 molecule interaction. The change in carrier density and Fermi level is also calculated after HNO3 treatment for all the samples. Our results demonstrate chemical modification is an effective approach to modulate the electrical properties CVD grown SLG for diverse applications.