Journal of Materiomics ( IF 8.4 ) Pub Date : 2020-12-15 , DOI: 10.1016/j.jmat.2020.12.005 A.C. García-Wong , D. Pilloud , S. Bruyère , D. Mangin , S. Migot , J.F. Pierson , F. Capon
In this paper, vanadium nitride (VN) thin films have been deposited on Al substrates by reactive magnetron sputtering. Thermochromic VO2 films have been obtained by air oxidation of VN samples performed at three temperatures (450, 525 and 550 °C) at various durations (lower than 50 min). X-ray diffraction and Raman spectrometry of the VN oxidized films indicate that VO2 and V2O5 are the only phases produced during the oxidation process. Vanadium dioxide is the first oxide formed. It coexists with VN in a long period at 450 °C or suddenly disappears at 525 and 550 °C. Whatever the temperature, V2O5 is exclusively detected after the total oxidation of VN. This oxide is detrimental to the thermochromic performance of films. The emissivity-switching properties of the oxidized films were analyzed by infrared camera in the 7.5–13 μm range. The comparison among all the samples exhibiting a thermochromic behavior shows that the maximum emissivity switch is independent of the oxidation temperature and the surface morphology of the samples. These results could open a new strategy in the investigation of VN oxidation as a method to obtain VO2, along with an insight into the correlation between surface morphology and optical properties.
中文翻译:
氮化钒空气氧化制热变色VO 2薄膜的表面形貌与光学性质的关系
在本文中,已经通过反应磁控溅射将氮化钒(VN)薄膜沉积在Al基板上。通过在三个温度(450、525和550°C)下以不同的持续时间(低于50分钟)对VN样品进行空气氧化,可获得热致变色VO 2膜。VN氧化膜的X射线衍射和拉曼光谱表明,VO 2和V 2 O 5是氧化过程中产生的唯一相。二氧化钒是形成的第一氧化物。它在450°C下与VN长期共存,或者在525和550°C下突然消失。无论温度如何,V 2 O 5仅在VN完全氧化后才能检测到。该氧化物对膜的热致变色性能有害。用红外热像仪在7.5-13μm范围内分析了氧化膜的发射率转换特性。所有表现出热致变色行为的样品之间的比较表明,最大发射率转换与样品的氧化温度和表面形态无关。这些结果可以为研究VN氧化作为一种获得VO 2的方法开辟新的策略,并深入了解表面形态与光学性质之间的相关性。