ExperimentalThe monomers lla and Ilb, and the precursor polymers la and Ib, were for their assistance in using these facilities. X.-M.Z. thanks Dr. Christian Marzolin for providing the spin-on glass used in the experiments. The authors thank Prof. M. Prentiss and Ben Brown for helping them to test the polymeric waveguides. Adv. Mnter. 1996,8, No. 10 0 VCH Verlagsgesellschaft mbH, 0-69469 Weinheim, I996 0935-9648/96/
The reliable fabrication of nanostructures is polymer materials, i.e. structures with feature sizes below 100 nm, is an important goal if progress in the application of such materials in electronic, magnetic, and optical devices is to be maintained. Replica molding has been used extensively to produce micrometer sized features. Here, the technique is extended to the nanometer regime such as that shown in the figure. fig.
This paper describes a technique to measure the surface density of the defects in self-assembled monolayers (SAMs) of hexadecanethiolates on gold that lead to etching of the gold when the system is etched with aqueous ferricyanide solution. This technique uses two steps of amplification through chemical reaction to convert pinhole defects in SAMs into easily imaged, micron-scale pits in an underlying Si support. With this technique, it is possible to evaluate the density of defects in SAMs and in the structures prepared by using SAMs as resists under conditions that may be encountered in lithographic processing. At present, the lowest density of pits that we have measured for SAMs of hexadecanethiolates on 50 nm thick gold is ∼5 pits/mm 2 . This density is an upper limit for the density of defects that expose bare gold to the etching solution or that comprise regions of SAM sufficiently thin that the SAM is not able to block access of the etchant to the gold. a This area is an arbitrary choice. There is no direct evidence indicating the size of the defects detected electrochemically. b From present study. See text for experimental details.
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