Organic vertical field effect transistors: Achieving high on-off ratio and vertical integration with OLEDs (Presentation Recording)

Abstract

Organic vertical field effect transistors (VFETs) have been explored to enhance the output current level and device operation speed due to the inherent low carrier mobility of organic semiconductors. However, most of VFETs reported to date involve a complex source electrode patterning process owing to their operation mechanism. Here, we investigate on VFETs based on C60 that do not require complex source electrode patterning process by insulting the top surface of a source electrode embedded in C60 layer [1]. In a VFET structure studied in this work, current flow is controlled by the electric field between a gate and a source electrode embedded within an active layer which is called bottom active layer. Based on its operation mechanism, several geometrical parameters such as (i) bottom active layer thickness; (ii) presence of a charge blocking layer and its thickness ensuring insulating properties; and (iii) the width of electrodes are identified as key factors influencing device performance. Through the device optimization with these parameters, the proposed organic VFETs exhibit a large on/off ratio of 6×10^5 and output current that is greater than that of a conventional C60 based OTFT with a similar device dimension. In order to show the benefit of VFETs, a single-pixel organic light-emitting diode (OLED) is integrated vertically with the VFETs under study.