Nanoscale Doping of Polymeric Semiconductors with Confined Electrochemical Ion Implantation

Abstract

Nano-resolved doping of polymeric semiconductors can overcome scaling limitations toward highly integrated flexible electronics, but remains a fundamental challenge. Here, we report a general methodology for achieving nanoscale ion-implantation-like electrochemical doping of polymeric semiconductors by confining counterion electromigration in an electrolyte. The process is mediated by adjusting the electrolyte glass transition temperature (Tg) and the operating temperature (T), which generates a highly localized electric field distribution and anisotropic ion migration that nearly vertical to the nanotip electrodes. The confined doping produces a record resolution of 56 nm with a lowest lateral diffusion length (LDL) down to 6 nm, which approaches the polaron delocalization limit of the host polymer. Moreover, we demonstrate a universal exponential dependence of the doping resolution on the temperature difference (Tg−T) that can be used to depict the doping resolution for almost infinite polymeric semiconductors. Our results may stimulate the design and nanofabrication of novel polymer devices based on the nanoscale defined doping patterns.