The effect of film thickness on the square resistance of graphene electrodes in graphene sensors

Graphene, a novel type of two-dimensional material, has been widely used in sensor applications due to its excellent electrical conductivity, thermal properties, and high surface area. This study investigates the effect of film thickness on the square resistance of graphene electrodes in graphene-based sensors. Graphene films with varying thicknesses were fabricated. Their sheet resistance was measured using the four-point probe method to analyze the influence of thickness on electrical performance. Experimental results show that increasing film thickness significantly affects the conductivity of the electrodes. Specifically, when the film is thin, strong surface scattering leads to high resistance. As the thickness increases, surface scattering weakens, electrical conductivity improves, and sheet resistance decreases. However, further thickening of the film introduces more defects and grain boundaries, causing resistance to rise again. These findings suggest that controlling the film thickness can effectively optimize the electrical performance of graphene electrodes, thereby enhancing the sensitivity and response speed of graphene sensors. This research provides theoretical support for the design and optimization of graphene-based sensors and valuable insights for future studies.