Flicker Noise in Graphene Flake Networks as an Indicator of Their Suitability as Humidity Sensors

ABSTRACT Graphene flake dispersions can form conductive thin films via well‐established, scalable deposition methods, such as spin‐coating. These conductive graphene flake networks constitute sensing layers suitable for chemiresistive CMOS‐compatible humidity sensors. Electrical noise is a parameter that affects sensor performance, and minimizing it requires thorough knowledge of the noise and its sources specific to the application. In this work, we present a phenomenological study of noise in resistive graphene sensors made from different graphene flake dispersions. We measured noise as a function of the graphene flake type, thickness of the graphene flake network, and sensor area. We conducted noise and sensitivity measurements to select the most suitable flake type for humidity sensing. We studied the influence of the temperature on the sensitivity and noise, and evaluated the humidity‐dependent noise. Finally, a sensor operating mode is defined which enables humidity sensing well beyond the 1 % detection limit and with minimized resistance drift.