Multifunctional graphene sensor for detection of environment signals using a decoupling technique

Graphene is one of good candidates for application to multifunctional sensors due to its unique material properties, extremely high surface-to-volume ratio and ability to be effectively co-integrated on various substrates. However, the electrical properties of graphene are sensitive to most typical environment signals such as temperature, light, humidity, and gas. Therefore, to develop graphene-based multifunctional sensors, it is essential to identify multiple environment information values from the output characteristics of a single graphene sensor. In this study, we developed a temperature–illuminance multifunctional graphene sensor that can identify both temperature and illuminance values. We also propose a decoupling technique to enable the precise identification of temperature and illuminance values from the output characteristics of a sensor that has cross-sensitivity to the both inputs. This decoupling technique is developed based on the different gate-voltage dependence of the temperature- and illumination-induced modulations of the graphene conductivity. The results show that graphene can be used as a material for multifunctional sensors when combined with an appropriate decoupling technique for identifying various types of environment signals.