Surface acoustic wave (SAW) humidity sensors promise broad prospects for Internet of Things (IoT) applications due to the advantages of low cost, portability, and high sensitivity. However, previous researches mainly focused on developing SAW devices with higher resonant frequencies, or using new sensing materials to improve the performance of SAW humidity sensors. Few researches studied the specific response mechanism of SAW humidity sensors, which restricted further development of the sensors. In this paper, the sensing mechanism of a graphene oxide (GO) film-based SAW humidity sensor is thoroughly studied by investigating the mechanical and electrical parameters of the uniform GO membrane at different relative humidity (from 10% RH to 90% RH). After taking these parameters into consideration for the mechanism analysis, we quantitatively indicate that the mass loading (~800 ppm) and viscoelastic effects (~60 ppm) are the primary and secondary influence factors of the sensor’s humidity response respectively, while the acoustoelectric interaction has little effect on the sensitivity. [2020-0024]

中文翻译：

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涂有均匀氧化石墨烯膜的表面声波湿度传感器的特定传感机制研究

声表面波 (SAW) 湿度传感器由于具有低成本、便携性和高灵敏度的优势，为物联网 (IoT) 应用带来了广阔的前景。然而，以前的研究主要集中在开发具有更高谐振频率的 SAW 器件，或使用新的传感材料来提高 SAW 湿度传感器的性能。很少有研究研究SAW湿度传感器的具体响应机制，限制了传感器的进一步发展。在本文中，通过研究不同相对湿度（从 10% RH 到 90% RH）下均匀 GO 膜的机械和电气参数，深入研究了基于氧化石墨烯 (GO) 膜的 SAW 湿度传感器的传感机制。在将这些参数考虑在内进行机理分析后，我们定量地表明质量负载（~800 ppm）和粘弹性效应（~60 ppm）分别是传感器湿度响应的主要和次要影响因素，而声电相互作用对灵敏度的影响很小。[2020-0024]