Nano cone ITO thin films prepared by pulsed laser deposition for surface measurement of high-temperature components

Abstract

Semiconductor thin-film thermocouples (TFTCs) are widely used for temperature measurement of aero-engine components due to their large output and fast response. As a thermoelectric material, indium tin oxide (ITO) makes the device have very good thermoelectric merit because of its low resistivity, which is very suitable for the preparation of thin-film thermocouples. In this study, Pt-ITO thin-film thermocouple was fabricated on alumina ceramic substrate by pulsed laser deposition (PLD), and the microstructure and electrical properties of TFTCs prepared under different deposition conditions and annealing conditions were investigated. The results show that the ITO thin films prepared by PLD have a new type of nano cone structure and the resistivity of ITO thin films was only 2.76 × 10−4 Ω·cm when the substrate temperature was 600 °C. The Pt-ITO thin-film thermocouples can stable work for at 25–1300 °C and work in a short time at 1400 °C, and the average Seebeck coefficient is more than 50 µV/°C at 1300 °C. The response time of the prepared TFTC tested by pulsed laser is no more than 435 μs. These results provide an important basis for a potential application prospect of Pt-ITO TFTCs in the field of high-temperature measurement. It is further confirmed that the preparation of superior thermoelectric semiconductor materials by PLD is a promising method.