Lab talk
Nov 16, 2007
Large-scale local probe oxidation of OTS monolayers
Oxidative probe lithography of self-assembled monolayers is a novel and versatile route for the creation of chemically active surface patterns with high resolution that may be used in subsequent surface modification and self-assembly steps. The electro-oxidation method combines top-down surface patterning techniques and bottom-up self-assembly and subsequent surface modification steps, thereby enabling the planned hierarchical assembly of complex nanostructures. However, the use of a single AFM tip as a patterning tool is inherently slow. As there are commercial applications as well as spectroscopic characterization techniques the modification of large surface areas is required, so large-scale surface oxidation patterning tools are demanded.
Although the local probe oxidation technique is not limited to the use of AFM tips – electrodes and large electrodes as TEM grids or even water droplets may be applied – their application has disadvantages as they restrict the achievable resolution and freedom of pattern choice. In addition, since the oxidation of the monolayer only occurs in a narrow process window (pulse height and pulse duration), control over the oxidation process using macroscopic electrodes is critical.
In our work we report the use of automated AFM equipment as well as the operation of parallel cantilever arrays for large-scale local probe oxidation of octadecyl trichlorosilane (OTS) monolayers. Using both methods we demonstrate the large-scale surface electro-oxidative patterning of OTS monolayers as a step towards the large-scale preparation of an all probe-produced device.
About the author
Ulrich Schubert heads the laboratories of macromolecular chemistry and nanoscience at the Eindhoven University of Technology, and the laboratory of organic and macromolecular chemistry at Friedrich-Schiller-Universität, Jena. Current research on the field of nanoscience focuses on the development of new strategies for the planned smart functionalization of surfaces on the nanometer scale.
