Compositional engineering of oxygen in amorphous TiO2-x to enhance temperature sensitivity for high-temperature microbolometer applications

초록

This study investigates room-temperature-sputtered TiO2-x thin films as thermistor materials for microbolometers, enabling high thermal sensitivity and reliable operation up to 125 degrees C. By precisely controlling the oxygen content during sputtering deposition, oxygen-vacancy-related defect states in TiO2-x were systematically engineered. X-ray photoelectron spectroscopy reveals that suppressing oxygen-vacancy-induced shallow donor states establishes an optimal activation energy level to enhance thermally activated carrier modulation, leading to an increased temperature coefficient of resistance (TCR). As a result, the TiO2-x thin films exhibit a high TCR of -1.5% K-1 at 125 degrees C. The microbolometers exhibit a fast-thermal response with a time constant below 1.38 ms, together with an enhanced responsivity of 3.15 kV/W and a reduced noise voltage, resulting in a high specific detectivity of 1.25 & times; 108 cm & sdot;Hz1/2/W. These results demonstrate that oxygen-engineered TiO2-x thin films serve as reliable and scalable thermistor materials for high-temperature microbolometer applications.

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