Using soft lithography to fabricate gold nanoparticle patterns for bottom-gate field effect transistors

Abstract

In this study we developed an efficient method for the direct patterning of Au, through the self-assembly of gold nanoparticles (AuNPs) from colloidal solutions, onto Si substrates. We used an integrated process involving soft lithography and self-assembly to fabricate patterns of sub-micrometer AuNPs on the Si surface. By exploiting soft lithography, we obtained nanoscale patterns of self-assembled monolayers (SAMs) without the need for traditional photolithography or etching processes. After using soft lithography to pattern a SAM of (3-mercaptopropyl)trimethoxysilane on a Si surface, we immobilized AuNPs, synthesized in a two-phase system, to form the bottom layer. We then used a cross-linking agent, 1,6-hexanedithiol, to construct multiple layers of AuNP aggregates, ultimately self-assembling five-layer structures that we employed as nanoscale metal electrodes in the fabrication of organic field effect transistors (OFETs), which exhibited output characteristics, including sheet resistance, drain–source voltage, and drain–source current, similar to those of corresponding OFETs prepared using traditional processing.