Velásquez-García L F, Akinwande A I
Microsystems Technology Laboratories, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Office 39-657, Cambridge, MA 02139, USA.
Nanotechnology. 2008 Oct 8;19(40):405305. doi: 10.1088/0957-4484/19/40/405305. Epub 2008 Aug 26.
This paper describes the fabrication of large arrays (10(6) units in 1 cm(2)) of 100 µm tall, single-crystal silicon columns with submicron tip cross-sections. The columns are formed using thin film deposition and growth, reactive ion etching, and deep reactive ion etching. The columns can be either slightly tapered or have pencil-like morphology with nanoscaled tip diameter (41 nm). Conformal thin film coating was used to substantially and uniformly modify the porous structure and, thus, vary by orders of magnitude the fluid permeability of the structure. Gaps between the vertical pillars were varied between 9 µm and 50 nm. Isolated 45 nm diameter, 5 µm tall plasma enhanced chemical vapour deposited multi-walled carbon nanotubes (MWNTs) were grown on the top surface of the columns using a 7 nm thick evaporated Ni film as catalyst. Field emission characterization of the resulting structure was conducted and it is in agreement with scanning electron micrographs of the MWNTs.
本文描述了大面积阵列（每平方厘米10⁶个单元）的制备，该阵列由高度为100μm、尖端横截面为亚微米级的单晶硅柱组成。这些柱子通过薄膜沉积与生长、反应离子蚀刻和深反应离子蚀刻形成。柱子可以是略微锥形的，也可以是具有纳米级尖端直径（41nm）的铅笔状形态。采用保形薄膜涂层对多孔结构进行实质性和均匀改性，从而使结构的流体渗透率在数量级上发生变化。垂直柱之间的间隙在9μm至50nm之间变化。使用7nm厚的蒸发镍膜作为催化剂，在柱子的顶表面生长出孤立的、直径为45nm、高5μm的等离子体增强化学气相沉积多壁碳纳米管（MWNTs）。对所得结构进行了场发射表征，结果与MWNTs的扫描电子显微镜图像一致。
