Gate Insulators in Organic Field-Effect Transistors

TLDR

The choice of gate insulator is as critical as the semiconductor in OFETs, with researchers exploring many organic and inorganic materials and deposition techniques that influence the active interface and device performance. This review surveys recent advances in understanding insulator/semiconductor interfaces in OFETs, emphasizing dielectric effects and interface phenomena in polymeric and molecular semiconductors. The authors analyze literature and case studies from Philips and Avecia, examining dielectric effects and electronic transport in polymeric, molecular, and amorphous OSCs. Surface treatments on inorganic insulators markedly improve molecular ordering and enhance OFET device performance.

Abstract

In this paper, we review recent progress in the understanding of insulator/semiconductor interfaces in organic field-effect transistors (OFETs). We would like to emphasize that the choice of gate insulator is as important for high-quality OFET devices as the semiconductor itself, especially because of the unique transport mechanisms operating in them. To date researchers have explored numerous organic and inorganic insulator materials, some of them designed to improve the morphology of the organic semiconductor (OSC). Surface treatments, particularly on inorganic insulators, have been shown to influence significantly molecular ordering and device performance. In addition, the deposition technique used for the insulator and semiconductor layers has a further impact on the active interface. Dielectric related effects are reviewed here for a variety of polymeric and molecular semiconductors reported in the literature, with an emphasis on electronic transport. We also review in more detail experiences at Philips and the recent work at Avecia to clarify some of the interface phenomena using amorphous OSC.