A Monoclinic V_1-x-yTi_xRu_yO₂ Thin Film with Enhanced Thermal-Sensitive Performance

Preparing the thermal-sensitive thin films with high temperature coefficient of resistance (TCR) and low resistivity by a highly compatible process is favorable for increasing the sensitivity of microbolometers with small pixels. Here, we report an effective and process-compatible approach for preparing V_1-x-yTi_xRu_yO₂ thermal-sensitive thin films with monoclinic structure, high TCR, and low resistivity through a reactive sputtering process followed by annealing in oxygen atmosphere at 400 °C. X-ray photoelectron spectroscopy demonstrates that Ti⁴⁺ and Ru⁴⁺ ions are combined into VO₂. X-ray diffraction, Raman spectroscopy, and transmission electron microscopy reveal that V_1-x-yTi_xRu_yO₂ thin films have a monoclinic lattice structure as undoped VO₂. But V_1-x-yTi_xRu_yO₂ thin films exhibit no-SMT feature from room temperature (RT) to 106 °C due to the pinning effect of high-concentration Ti in monoclinic lattice. Moreover, RT resistivity of the V_0.8163Ti_0.165Ru_0.0187O₂ thin film is only one-eighth of undoped VO₂ thin film, and its TCR is as high as 3.47%/°C.