Abstract Elaboration of VO2 films with good thermochromic properties remains a challenge because it is mandatory to avoid other intermediate phases belonging to the vanadium-oxygen system. In this work, we propose vanadium nitride (VN) as a new precursor to obtain thermochromic VO2. VN films were reactively sputter-deposited on Si substrates by using an in-line semi-industrial machine. The films of 175 nm thickness were submitted to an annealing process implemented at different durations at 450 °C. X-ray diffraction and Raman spectrometry were performed for structural characterizations of the oxidized films showing the presence of monoclinic VO2 in a wide range of oxidation time. As the annealing time increased, V2O5 appeared to affect the performance of the oxidized films. The TEM analysis carried out on the oxidized sample for 25 min showed that there is an abrupt interface between VN and VO2. The thermal-induced properties of the studied films were analyzed in terms of their electrical resistance employing a four-point probe method and their emissivity modulation properties by infrared camera. The results showed a thermochromic behavior for the samples oxidized in the range of 15–35 min. On the contrary, the presence of residual VN layers in samples oxidized for less than 15 min and V2O5 in the ones annealed for more than 35 min hindered the thermochromic behavior of these films. Bringing together all the characterization techniques used a phase diagram of VN oxidation was plotted. The results of this work suggest that VN is an interesting new precursor to synthesize thermochromic VO2 films.

中文翻译：

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溅射沉积氮化钒的氧化作为一种​​新的前驱体以实现热致变色 VO2 薄膜

摘要 制备具有良好热致变色性能的 VO2 薄膜仍然是一个挑战，因为必须避免属于钒氧系统的其他中间相。在这项工作中，我们提出氮化钒 (VN) 作为获得热致变色 VO2 的新前体。VN 薄膜通过使用在线半工业机器反应溅射沉积在 Si 衬底上。175 nm 厚的薄膜在 450 °C 下进行了不同持续时间的退火工艺。对氧化膜的结构表征进行了 X 射线衍射和拉曼光谱分析，表明在很宽的氧化时间范围内存在单斜晶 VO2。随着退火时间的增加，V2O5 似乎会影响氧化膜的性能。对氧化样品进行 25 分钟的 TEM 分析表明，VN 和 VO2 之间存在突变界面。所研究薄膜的热诱导特性通过使用四点探针方法的电阻和红外相机的发射率调制特性进行分析。结果表明，在 15-35 分钟范围内氧化的样品具有热致变色行为。相反，氧化时间小于 15 分钟的样品中残留的 VN 层的存在和退火时间超过 35 分钟的样品中的 V2O5 阻碍了这些薄膜的热致变色行为。将所有使用的表征技术结合在一起，绘制了 VN 氧化的相图。这项工作的结果表明，VN 是合成热致变色 VO2 薄膜的一种有趣的新前体。