High-density integration of carbon nanotubes via chemical self-assembly http://www.nature.com/nnano/journal/vaop/ncurrent/abs/nnano.2012.189.html http://www-03.ibm.com/press/us/en/pressrelease/39250.wss >Here, we show that ion-exchange chemistry can be used to fabricate arrays > of individually positioned carbon nanotubes with a density as high as > 1 × 109 cm−2―two orders of magnitude higher than previous reports8, 9. >With this approach, we assembled a high density of carbon-nanotube >transistors in a conventional semiconductor fabrication line >and then electrically tested more than 10,000 devices in a single chip.