Structural and electric response of ITO/In₂O₃ transparent thin film thermocouples derived from RF sputtering at room temperature

Transparent thin film thermocouples have unique characteristics that it can be applied when permit minimal optical interference at in-situ temperature measurement. ITO/In₂O₃ thin film thermocouples were prepared on fused quartz glasses at room temperature by RF magnetron sputtering. For contrast, ITO thin films post-annealed at different temperatures were investigated accordingly. All films showed good conductivities, smooth surface morphology and high transmission, indicating negligible affection of the post-annealing temperature. The as-deposited ITO film has a Seebeck coefficient of 84.4 µV ºC⁻¹. The thermoelectric voltage of 13.6 mV and significantly lower drift rate of 2.39 °C h⁻¹ were obtained at 190 °C for ITO/In₂O₃ thin film thermocouples without any heat treatment. This makes the ITO/In₂O₃ transparent thin film thermocouples great potential as a promising temperature sensor.