Low-noise room-temperature terahertz detector based on the photothermoelectric effect of graphene oxide-Bi films

Graphene has a very wide range of applications in terahertz (THz) photothermoelectric (PTE) detection due to its unique optical properties, but its high thermal conductivity leads to less than ideal performance of graphene PTE detectors. We experimentally demonstrate a method using UV/ozone to oxidize graphene, breaking the C–C bond by UV irradiation on the graphene surface and reacting with the excited oxygen atoms to promote the release of CO2, CO gas from the surface defects to produce hole structures by oxidative etching of graphene. Bi was assembled at the surface defects by liquid phase treatment to form graphene oxide (GO) - Bi films. The surface feature morphology was analyzed by SEM and XPS, and the optimal treatment time was found by setting control groups (G-0 to G-5) for UV/ozone oxidation. The devices are able to achieve a responsivity of 0.226 V/W for 0.22 THz and a value of NEP about 1.34 nW/√Hz. Simple preparation method provides new ideas for designing terahertz detectors.