Dickey Michael D, Weiss Emily A, Smythe Elizabeth J, Chiechi Ryan C, Capasso Federico, Whitesides George M
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
ACS Nano. 2008 Apr;2(4):800-8. doi: 10.1021/nn800036r.
This paper describes a simple technique for fabricating uniform arrays of metal and metal oxide nanotubes with controlled heights and diameters. The technique involves depositing material onto an anodized aluminum oxide (AAO) membrane template using a collimated electron beam evaporation source. The evaporating material enters the porous openings of the AAO membrane and deposits onto the walls of the pores. The membrane is tilted with respect to the column of evaporating material, so the shadows cast by the openings of the pores onto the inside walls of the pores define the geometry of the tubes. Rotation of the membrane during evaporation ensures uniform deposition inside the pores. After evaporation, dissolution of the AAO in base easily removes the template to yield an array of nanotubes connected by a thin backing of the same metal or metal oxide. The diameter of the pores dictates the diameter of the tubes, and the incident angle of evaporation determines the height of the tubes. Tubes up to approximately 1.5 mum in height and 20-200 nm in diameter were fabricated. This method is adaptable to any material that can be vapor-deposited, including indium-tin oxide (ITO), a conductive, transparent material that is useful for many opto-electronic applications. An array of gold nanotubes produced by this technique served as a substrate for surface-enhanced Raman spectroscopy: the Raman signal (per molecule) from a monolayer of benzenethiolate was a factor of approximately 5 x 10(5) greater than that obtained using bulk liquid benzenethiol.
本文介绍了一种用于制造高度和直径可控的金属及金属氧化物纳米管均匀阵列的简单技术。该技术包括使用准直电子束蒸发源将材料沉积到阳极氧化铝（AAO）膜模板上。蒸发的材料进入AAO膜的多孔开口并沉积在孔壁上。膜相对于蒸发材料柱倾斜，因此孔开口在内壁上投射的阴影确定了管的几何形状。蒸发过程中膜的旋转确保了孔内的均匀沉积。蒸发后，将AAO在碱中溶解可轻松去除模板，从而得到由相同金属或金属氧化物的薄衬底连接的纳米管阵列。孔的直径决定了管的直径，蒸发的入射角决定了管的高度。制造出了高度约达1.5μm、直径为20 - 200nm的管。该方法适用于任何可进行气相沉积的材料，包括氧化铟锡（ITO），这是一种对许多光电子应用有用的导电透明材料。通过该技术制备的金纳米管阵列用作表面增强拉曼光谱的基底：单层苯硫醇盐的拉曼信号（每分子）比使用本体液态苯硫醇获得的信号大约高5×10⁵倍。
