Probe-Based Electro-Oxidative Lithography of OTS SAMs Deposited onto Transparent ITO Substrates

Transparent conductive oxides like indium tin oxide (ITO) play a pivotal role in a wide range of innovative applications, such as new generations of solar cells. In many of these applications the tailoring of surface properties on the nanometer scale represents a highly desirable target. The local oxidation of self-assembled monolayers (SAMs) using a scanning probe is a promising technique to achieve surface modifications on the nanometer scale. So far, electro-oxidative lithography of SAMs has been reported mainly on Si wafers while there are no previous reports on transparent oxides. Here, we report the oxidative lithography of n-octadecyltrichlorosilane (OTS) SAM deposited onto an ITO layer. A local overoxidation of the substrate is observed while the simultaneously occurring monolayer oxidation is indirectly confirmed by the site-selective deposition of silver nanoparticles onto electro-oxidized areas. The process of lithography is compared to that on OTS-Si substrates and its mechanism is systematically investigated by means of scanning Kelvin probe microscopy (SKPM).