Band gap tuning and enhanced photosensitivity of nitrogenated TiO2via graphene incorporation for low-voltage UV photodetectors

Abstract

The emergence of metal oxide-based photodetectors has been on the rise in recent years, owing to the tunability of their optical band gap and photosensitivity. The current study focuses on tuning the band gap of nitrogenated TiO₂ (N–TiO₂) using reduced graphene oxide. The incorporation of low doses of graphene (0.0394 and 0.0432 g) into the N–TiO₂ shows widening of the band gap (2.52 → 2.79 → 2.95 eV). The electrical conductivity properties obtained from the current–voltage sweep show a decrease as the graphene concentration increases and are consistent with the widening of the band gap. The photosensitivity properties of a high concentration of graphene-supported N–TiO₂ depict improved response at low voltage (0.5 V) in comparison to pristine N–TiO₂ by 14.7%, which suggests that graphene incorporation supports photodetection at low voltage. The study proposes that incorporating graphene into N–TiO₂ nanostructures can be used to enhance the sensitivity of low-voltage UV photodetector devices.