氧化石墨烯薄膜厚度对元件湿敏性能的影响

Influence of the Thickness of Graphene Oxide Thin Film on Humidity Sensitivity

以改进Hummers法获得的氧化石墨为原料制备氧化石墨烯，采用旋涂法通过使用不同浓度的氧化石墨烯水相分散液制备不同厚度的氧化石墨烯薄膜湿敏元件。采用X射线衍射仪（XRD）、红外光谱仪（FT-IR）、扫描电子显微镜（SEM）、扫描探针显微镜（SPM）和湿度测试仪对氧化石墨烯薄膜的结构、形貌和湿敏性能进行分析。结果表明，在室温下随氧化石墨烯薄膜厚度减小（139nm、102nm、65nm、35nm和18nm），湿敏元件响应时间由10S缩短至2S，恢复时间由37S缩短至8S；在11．3％-93．6％RH范围内，湿敏元件电阻随湿度增加而显著减小，从兆欧级减小至千欧级，变化达到3个数量级；湿敏元件的最佳响应时间为2S，恢复时间为8S，最高灵敏度可迭96．06％，具有较好的湿敏性能。

Graphene oxide （GO） was prepared from graphite oxide which was prepared using modified Hum- mers method. And the GO film samples were prepared by spin coating method with the different concentration of GO aqueous dispersion. Analyses for the structure, surface topography, and humidity sensing behavior of the samples were carried out by AFM, XRD, FT-IR, SEM, and humidity sensing experimental device. Results showed that the recovery time decreased from 37 s to 8 s with the thickness of the samples decreased from 139 nm to 18 nm （139 nm, 102 nm, 65 nm, 35 nm and 18 nm）. As the relative humidity increased from 11.3% to 93.6%RH, the resistance of the samples were significantly reduced. The response time and recovery time of the humidity sensors were 2 s and 8 s respectively, and the sensitivity approached 96. 06%RH, suggesting a good humidity sensing property at room tem- perature.