Vertical Organic Field‐Effect Transistors

Abstract

Field-effect transistors are the fundamental building blocks for electronic circuits and processors. Compared with inorganic transistors, organic field-effect transistors (OFETs), featuring low cost, low weight, and easy fabrication, are attractive for large-area flexible electronic devices. At present, OFETs with planar structures are widely investigated device structures in organic electronics and optoelectronics; however, they face enormous challenges in realizing large current density, fast operation speed, and outstanding mechanical flexibility for advancing their potential commercialized applications. In this context, vertical organic field-effect transistors (VOFETs), composed of vertically stacked source/drain electrodes, could provide an effective approach for solving these questions due to their inherent small channel length and unique working principles. Since the first report of VOFETs in 2004, impressive progress has been witnessed in this field with the improvement of device performance. The aim of this review is to give a systematical summary of VOFETs with a special focus on device structure optimization for improved performance and potential applications demonstrated by VOFETs. An overview of the development of VOFETs along with current challenges and perspectives is also discussed. It is hoped that this review is timely and valuable for the next step in the rapid development of VOFETs and their related research fields.

Ion‐Gated Transistor: An Enabler for Sensing and Computing Integration

“…Vertical field-effect transistors (vFETs) have been developed to improve saturation current and switching frequency. [64][65][66] A larger saturation current means that a smaller operating voltage can be obtained under the same current, which is highly useful in reducing power consumption. It is reasonable to believe that vertical structure would be in favor of the power consumption and switching speed of IGTs as well.…”

“…[10,11,14] Compared with the planar configuration of the IGTs, vertical structure might be more convenient for meeting these requirements. [64][65][66] Lenz et al adopted a clever method to fabricate IGTs with vertical structure. [51] Figure 8a,b shows the structure diagram of the vertical IGT.…”

Organic Photodetectors for Next‐Generation Wearable Electronics

“…The reason for this is primarily due to the difficulty in fabricating vertical organic fieldeffect transistors. [57] The channel length of lateral organic fieldeffect transistors (typically greater than ≈5-10 µm) is much longer compared to organic photodiodes and the charge transport length of organic materials, and therefore existing organic photo transistors exhibit very poor photovoltaic efficiencies. [58] To the best of our knowledge, organic phototransistor with ver tical structure is yet to be achieved, and therefore all organic photo transistors that we discuss in this review have lateral device structures.…”

Organic Light‐Emitting Transistors: Advances and Perspectives

“…In contract, one can find fewer n ‐type organic semiconductor materials [see some recent reviews for organic field‐effect transistor (FETs)] than p ‐type organic semiconductor materials (Table and Figure ) . This renders novel and innovative electron‐transporting materials quite desirable as balanced charge injection is a major requirement for many LET devices.…”