Development of Graphene-Doped TiO2-Nanotube Array-Based MIM-Structured Sensors and Its Application for Methanol Sensing at Room Temperature

This work concerns the development of a good quality graphene doped TiO2 nanotube array sensor for efficient detection of methanol. A pure and graphene doped TiO2 nanotube array was synthesized by electrochemical anodization. Morphological, structural and optical characterizations were performed to study the samples. Both the nanotube samples were produced in Au/TiO2 nanotube/Ti type MIM-structured devices. Pure and graphene-doped TiO2 nanotubes offered a response magnitude of 20% and 28% to 100 ppm of methanol at room temperature, respectively. Response/Recovery time was fast for the graphene doped TiO2 nanotube array (34 s/40 s) compared to a pure TiO2 nanotube array (116 s/576 s) at room temperature. This study confirmed the notable enhancement in methanol sensing due to the formation of local heterojunctions between graphene and TiO2 in the hybrid sample.