Fabrication and characterization of La0.8Sr0.2CrO3/In2O3 thin film thermocouple for high temperature sensing

La0.8Sr0.2CrO3/In2O3 ceramic-based thin film thermocouple (TFTC) was successfully fabricated by using radio frequency (RF) sputtering method. The phases structures and morphologies of La0.8Sr0.2CrO3 and In2O3 thin films were investigated by XRD and SEM, respectively. La0.8Sr0.2CrO3 thin film showed orthorhombic phase and shuttle structure through post-annealing. The crystalization properties of In2O3 thin film were enhanced with the post-annealing. At the same time, their electrical conductivities were improved with the post-annealing process. When the thermoelectric properties of La0.8Sr0.2CrO3 and In2O3 were investigated by coupling with Pt thin film electrodes, both of them showed good linear relationship with temperature difference. The TFTC fabricated by La0.8Sr0.2CrO3 and In2O3 thin films showed very good performance with good stable, reproducible thermoelectric voltage, and high sensitivity at higher temperature. The sensitivity of La0.8Sr0.2CrO3/In2O3 thin film thermocouple was 305.8 μV/oC. The dynamic thermal response of the TFTC demonstrated that it could monitor the real-time and in-situ temperature successfully.