Most resistance-type humidity sensors exhibit negative humidity sensitivity, i.e., their resistance decreases with a corresponding increase in humidity. This is primarily attributed to the dominant role of ionic conduction in adsorbed water. In this work, a humidity sensor based on a p-type reduced graphene oxide (p-rGO) with positive humidity sensitivity is proposed. Moreover, its positive humidity sensing response is further enhanced by n-type WS2 nanoparticles modification. The results show that both rGO and rGO/WS2 humidity sensors have good linear response in the relative humidity (RH) range of 0% − 91.5%. The sensitivity of the rGO/WS2 humidity sensor is 1.87 times that of rGO humidity sensor, which is mainly attributed to p–n heterojunction between rGO and WS2. Besides, the rGO/WS2 humidity sensor has small humidity hysteresis (~ 3% RH) and good repeatability. This work demonstrates a humidity sensor based on rGO/WS2 composite film and provides a facile route for fabricating humidity sensor with positive humidity sensing properties.

中文翻译：

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用 n-WS2 纳米粒子装饰的 p 还原氧化石墨烯增强的正湿敏行为

大多数电阻式湿度传感器表现出负湿度敏感性，即它们的电阻随着湿度的增加而降低。这主要归因于离子传导在吸附水中的主导作用。在这项工作中，提出了一种基于具有正湿度敏感性的 p 型还原氧化石墨烯 (p-rGO) 的湿度传感器。此外，n 型 WS2 纳米颗粒改性进一步增强了其正湿度传感响应。结果表明，rGO 和 rGO/WS2 湿度传感器在 0% - 91.5% 的相对湿度 (RH) 范围内都具有良好的线性响应。rGO/WS2 湿度传感器的灵敏度是 rGO 湿度传感器的 1.87 倍，这主要归因于 rGO 和 WS2 之间的 p-n 异质结。除了，rGO/WS2 湿度传感器具有较小的湿度滞后 (~ 3% RH) 和良好的重复性。这项工作展示了一种基于 rGO/WS2 复合薄膜的湿度传感器，并为制造具有正湿度传感特性的湿度传感器提供了一条简便的途径。