Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory, University of Illinois, Urbana-Champaign, IL 61801, USA.
Nanotechnology. 2010 Feb 26;21(8):85702. doi: 10.1088/0957-4484/21/8/085702. Epub 2010 Jan 25.
We describe a pulsed measurement technique for suppressing hysteresis for carbon nanotube (CNT) device measurements in air, vacuum, and over a wide temperature range (80-453 K). Varying the gate pulse width and duty cycle probes the relaxation times associated with charge trapping near the CNT, found to be up to the 0.1-10 s range. Longer off times between voltage pulses enable consistent, hysteresis-free measurements of CNT mobility. A tunneling front model for charge trapping and relaxation is also described, suggesting trap depths up to 4-8 nm for CNTs on SiO2. Pulsed measurements will also be applicable for other nanoscale devices such as graphene, nanowires, or molecular electronics, and could enable probing trap relaxation times in a variety of material system interfaces.
我们描述了一种用于抑制碳纳米管（CNT）器件在空气、真空中以及很宽的温度范围（80-453 K）下测量时的滞后现象的脉冲测量技术。通过改变栅极脉冲宽度和占空比，可以探测与 CNT 附近电荷俘获相关的弛豫时间，发现弛豫时间范围可达 0.1-10 s。在电压脉冲之间增加更长的关断时间可以实现 CNT 迁移率的一致、无滞后测量。还描述了一种用于电荷俘获和弛豫的隧穿前沿模型，表明在 SiO2 上的 CNT 中陷阱深度高达 4-8nm。脉冲测量也将适用于其他纳米级器件，如石墨烯、纳米线或分子电子学，并且可以在各种材料系统界面中探测陷阱弛豫时间。
