A Novel Graphene-Based Temperature Sensor With a TiN/Si 3 N 4 Protective Layer for High Temperature up to 800 °C Applications

Temperature sensors are extensiv-ely utilized in various fields, including aero engines, consumer electronics, and health monitoring. Conventional temperature sensors are typically limited to measurements below 200 °C, rendering them inadequate for applications requiring temperature monitoring in extreme high-temperature environments. This paper presents a micrometer-scale high temperature resistant temperature sensor based on graphene. The device employs graphene as the sensing layer and incorporates a designed silicon nitride/titanium nitride (Si3N4/TiN) composite film as a protective layer. This structure effectively prevents the high temperature oxidation of graphene, thereby extending its operational temperature range. Experimental results demonstrate that a protective layer consisting of a 100 nm TiN layer and a 500 nm Si3N4layer exhibits excellent protective performance. The sensor operates effectively in air across a temperature range of 25 °C to 800 °C, exhibiting a high temperature coefficient of resistance (TCR) of 0.26 %•°C⁻¹, along with long-term stability at room temperature. In summary, this device features a micrometer-scale structure, enables array-based fabrication, and demonstrates a high TCR and high-temperature tolerance up to 800 °C. This work offers new insights for the development of graphene-based high-temperature-resistant temperature sensors and expands their potential for diverse applications.