Carbon nanotube (CNT) thin film transistors (TFTs) have demonstrated great potential for application in highly sensitive biosensors and large‐area electronics. However, research on the electrical behavior of long‐channel CNT TFTs is lacking; thus, the purposeful improvement in the performance of biosensors or circuits is difficult. In this study, the electrical transport characteristics of ionic‐liquid‐gate CNT TFTs with channel lengths (Lch) ranging from 10 to 400 µm are investigated. The CNT TFTs present classical drift‐diffusion transport at on‐state with a carrier mobility of around 27 cm2 V−1 s−1. In the subthreshold region of the CNT TFTs, an abnormal Lch‐dependent subthreshold swing (SS) relationship, named as the long‐channel effect (LCE)is observed, where SS worsens with increasing Lch. The existence of the junctions between the CNTs results in an unconventional density of states for carriers and a large series resistance for sharing the gate voltage; this dominates the abnormal scaling behavior in the subthreshold region by degrading the electrostatic integrity. The discovery of the abnormal LCE can aid in the construction of device models and purposefully improve the performance of CNT TFTs for biosensors and other large‐scale electronic applications.

中文翻译：

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随机取向碳纳米管薄膜晶体管中的长通道效应


碳纳米管 （CNT） 薄膜晶体管 （TFT） 在高灵敏度生物传感器和大面积电子产品中显示出巨大的应用潜力。然而，缺乏对长通道 CNT TFT 电性能的研究;因此，有目的地改进生物传感器或电路的性能是很困难的。在本研究中，研究了通道长度 （Lch） 范围为 10 至 400 μm 的离子-液-栅 CNT TFT 的电传输特性。CNT TFT 在导通状态下呈现经典的漂移-扩散传输，载流子迁移率约为 27 cm2 V-1 s-1。在 CNT TFT 的亚阈值区域中，观察到异常的 Lch 依赖性亚阈值摆动 （SS） 关系，称为长通道效应 （LCE），其中 SS 随着 Lch 的增加而恶化。CNT 之间结的存在导致载流子的状态密度非常规，共享栅极电压时具有较大的串联电阻;这通过降低静电完整性来主导亚阈值区域的异常结垢行为。异常 LCE 的发现有助于构建器件模型，并有目的地提高用于生物传感器和其他大规模电子应用的 CNT TFT 的性能。