Mechanical Engineering Department, University of California at Berkeley, Berkeley, CA, USA.
Nanotechnology. 2011 Sep 7;22(36):365704. doi: 10.1088/0957-4484/22/36/365704. Epub 2011 Aug 11.
Comprehensive studies on the sheet and contact resistances of vertically aligned carbon nanotube (CNT) forests with as-grown bottom contacts to the metal layer have been conducted. Using microfabrication and four distinct methods: (1) the transfer length method (TLM), (2) the contact chain method, (3) the Kelvin method, and (4) the four point probe method, we have designed multiple testing devices to characterize the resistances of CNT-forest-based devices. Experimental results show that devices based on stripe-shaped CNT forests 100 µm in height and 100 µm in width have a sheet resistance of approximately [Formula: see text]. The corresponding specific contact resistance to the molybdenum layer is roughly 5 × 10(4) Ω µm(2). Consistency of the results from the four different methods validates the study. After two months of storage of the CNT forest samples in open air, less than 0.9% deviations in the resistance values were observed. We further demonstrated one application of CNT forests as an NH(3) gas sensor and measured 0.5 ppm of sensing resolution with a detection response time of 1 min.
我们对具有底部接触金属层的垂直排列碳纳米管 (CNT) 森林的片电阻和接触电阻进行了综合研究。使用微制造和四种不同的方法：（1）传输线方法 (TLM)，（2）接触链方法，（3）开尔文方法，和（4）四点探针方法，我们设计了多个测试设备来表征 CNT 森林器件的电阻。实验结果表明，基于高度为 100 µm、宽度为 100 µm 的条状 CNT 森林的器件具有约为 [Formula: see text]的片电阻。与钼层的相应特定接触电阻约为 5×10(4) Ω µm(2)。四种不同方法的结果一致性验证了该研究。将 CNT 森林样品在开放空气中储存两个月后，观察到电阻值的偏差小于 0.9%。我们进一步展示了 CNT 森林作为 NH(3)气体传感器的一种应用，并测量到 0.5 ppm 的感应分辨率，检测响应时间为 1 分钟。
