Yu Woo Jong, Chae Sang Hoon, Vu Quoc An, Lee Young Hee
Department of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 16419, South Korea.
Samsung-SKKU Graphene Center (SSGC), Sungkyunkwan University, Suwon 16419, South Korea.
Sci Rep. 2016 Aug 1;6:30836. doi: 10.1038/srep30836.
While several approaches have been developed for sorting metallic (m) or semiconducting (s) single-walled carbon nanotubes (SWCNTs), the length of SWCNTs is limited within a micrometer, which restricts excellent electrical performances of SWCNTs for macro-scale applications. Here, we demonstrate a simple sorting method of centimetre-long aligned m- and s-SWCNTs. Ni particles were selectively and uniformly coated along the 1-cm-long m-SWCNTs by applying positive gate bias during electrochemical deposition with continuous electrolyte injection. To sort s-SWCNTs, the Ni coating was oxidized to form insulator outer for blocking of current flow through inner m-SWCNTs. Sorting of m-SWCNTs were demonstrated by selective etching of s-SWCNTs via oxygen plasma, while the protected m-SWCNTs by Ni coating remained intact. The series of source-drain pairs were patterned along the 1-cm-long sorted SWCNTs, which confirmed high on/off ratio of 10(4)-10(8) for s-SWCNTs and nearly 1 for m-SWCNTs.
虽然已经开发出几种用于分离金属性（m）或半导体性（s）单壁碳纳米管（SWCNT）的方法，但SWCNT的长度被限制在微米范围内，这限制了SWCNT在宏观尺度应用中的优异电学性能。在此，我们展示了一种简单的方法来分离厘米长的排列整齐的m型和s型SWCNT。通过在连续注入电解液的电化学沉积过程中施加正栅极偏压，镍颗粒沿着1厘米长的m型SWCNT被选择性地、均匀地包覆。为了分离s型SWCNT，镍涂层被氧化形成绝缘外层，以阻止电流通过内部的m型SWCNT。通过氧等离子体对s型SWCNT进行选择性蚀刻来证明对m型SWCNT的分离，而被镍涂层保护的m型SWCNT保持完整。沿着1厘米长的已分离SWCNT对源极-漏极对进行图案化，这证实了s型SWCNT的开/关比高达(10^4 - 10^8)，而m型SWCNT的开/关比接近1。
