Hysteresis caused by water molecules in carbon nanotube field-effect transistors
Hysteresis caused by water molecules in carbon nanotube field-effect transistors
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DOI：
10.1021/nl0259232
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发表时间：
2003-02-01
期刊：
影响因子：
10.8
通讯作者：
Dai, HJ
中科院分区：
文献类型：
--
作者：
Kim, W;Javey, A;Dai, HJ
碳纳米管场效应晶体管通常由放置在暴露于环境中的SiO2表面的纳米管组成。结果表明，由于纳米管周围的水分子（包括靠近纳米管的SiO2表面结合水）捕获电荷，晶体管的电特性出现了滞后。在真空中，晶体管的磁滞现象仍然存在，因为在室温下，二氧化硅结合水在真空中不能完全解吸，这是二氧化硅表面化学中已知的现象。在干燥条件下加热可显著去除水分并减少晶体管的迟滞。几乎无磁滞的晶体管可以通过使用与SiO2上的硅醇基团氢键的聚合物（例如聚甲基丙烯酸甲酯（PMMA））钝化器件而获得。然而，纳米管湿度传感器可以探索合适的水敏涂层。这一结果可能对其他化学衍生材料制成的场效应晶体管具有启示意义。
Carbon nanotube field-effect transistors commonly comprise nanotubes lying on SiO2 surfaces exposed to the ambient environment. It is shown here that the transistors exhibit hysteresis in their electrical characteristics because of charge trapping by water molecules around the nanotubes, including SiO2 surface-bound water proximal to the nanotubes. Hysteresis persists for the transistors in vacuum since the SiO2-bound water does not completely desorb in vacuum at room temperature, a known phenomenon in SiO2 surface chemistry. Heating under dry conditions significantly removes water and reduces hysteresis in the transistors. Nearly hysteresis-free transistors are obtainable by passivating the devices with polymers that hydrogen bond with silanol groups on SiO2 (e.g., with poly(methyl methacrylate) (PMMA)). However, nanotube humidity sensors could be explored with suitable water-sensitive coatings. The results may have implications to field-effect transistors made from other chemically derived materials.