Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
Nano Lett. 2014 May 14;14(5):2655-63. doi: 10.1021/nl500514y. Epub 2014 Apr 7.
Plasmonic nanoantennas create locally strongly enhanced electric fields in so-called hot spots. To place a relevant nanoobject with high accuracy in such a hot spot is crucial to fully capitalize on the potential of nanoantennas to control, detect, and enhance processes at the nanoscale. With state-of-the-art nanofabrication, in particular when several materials are to be used, small gaps between antenna elements are sought, and large surface areas are to be patterned, this is a grand challenge. Here we introduce self-aligned, bottom-up and self-assembly based Shrinking-Hole Colloidal Lithography, which provides (i) unique control of the size and position of subsequently deposited particles forming the nanoantenna itself, and (ii) allows delivery of nanoobjects consisting of a material of choice to the antenna hot spot, all in a single lithography step and, if desired, uniformly covering several square centimeters of surface. We illustrate the functionality of SHCL nanoantenna arrangements by (i) an optical hydrogen sensor exploiting the polarization dependent sensitivity of an Au-Pd nanoantenna ensemble; and (ii) single particle hydrogen sensing with an Au dimer nanoantenna with a small Pd nanoparticle in the hot spot.
等离子体纳米天线在所谓的热点处产生局部强电场。要想充分利用纳米天线控制、检测和增强纳米尺度上的过程的潜力，就需要将相关的纳米物体以高精度放置在这样的热点中。采用最先进的纳米制造技术，特别是当需要使用多种材料时，人们会寻求天线元件之间的小间隙，并对大面积进行图案化处理，这是一个巨大的挑战。在这里，我们引入了自对准、自下而上和基于缩小孔胶体光刻的方法，该方法提供了（i）对随后沉积的形成纳米天线本身的颗粒的大小和位置的独特控制，以及（ii）允许将由所选材料组成的纳米物体递送到天线热点，所有这些都可以在一个光刻步骤中完成，如果需要，还可以均匀地覆盖几平方厘米的表面。我们通过（i）利用 Au-Pd 纳米天线组件的偏振相关灵敏度的光学氢气传感器；和（ii）在热点中具有小 Pd 纳米颗粒的 Au 二聚体纳米天线的单个粒子氢气传感，展示了 SHCL 纳米天线排列的功能。
