Title: Inkjet-printed rectifying metal-insulator-semiconductor (MIS) diodes for flexible electronic applications

Abstract

Inkjet printing is a well-accepted deposition technology for functional materials in the area of printed electronics. It allows the precise deposition of patterned functional layers on both, rigid and flexible substrates. Furthermore, inkjet printing is considered as up-scalable technology towards industrial applications. Many electronic devices manufactured with inkjet printing have been reported in the recent years. Some of the evident examples are capacitors, resistors, organic thin film transistors and rectifying Schottky diodes. [1, 2, 3] In this paper we report on the manufacturing of an inkjet-printed metal-insulator-semiconductor (MIS) diode on flexible plastic substrate. The structure is comprised of an insulating and a polymeric semiconducting layer sandwiched between two silver electrodes. The current vs. voltage characteristics are rectifying with rectification ratio up to 100 at |4 V|. Furthermore, they can carry high current densities (up to mA/cm 2 ) and have a low capacitance which makes them attractive for high frequency rectifying circuits. They are also an ideal candidate to replace conventional Schottky diodes for which the fabrication remains a challenge. This is because inkjet printing of Schottky diodes require additional processing steps such as intense pulsed light sintering (IPL sintering) [4] or post-treatments at high temperatures. The deposition of two different metal layers using inkjet printing e.g. Cu or Al with Ag is possible. However, the mentioned post treatment technologies might be incompatible with the already existing layer stack-e.g. it could degrade the organic semiconductor or can damage insulator which in this case is present in the MIS diode architecture.

Inkjet printed metal insulator semiconductor (MIS) diodes for organic and flexible electronic application

“…silver (bulk work function: 4.26 to 4.74 eV), copper (bulk work function: 4.53 to 4.98 eV), aluminium (bulk work function: 4.06 to 4.28 eV), poly (3,4 ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT:PSS, bulk work function: 5.1 eV) [20,21]. Either one of these functional conductive materials look simple to process, but in most of the cases it is challenging to appoint and locate them (having different work functions) adjacent to the semiconductor interface layer [22]. Recently, it has been reported that MIS structures show a rectifying behaviour [23][24][25][26].…”

“…On the contrary, a thick insulating layer with 50 to 200 nm will block the charge carrier flow and will not show rectification [26]. However, if the insulator layer is leaky due to an irregular morphology produced by the mutual interaction/blend of the semiconductor to insulator interfaces it can lead to a voltage controlled leakage and to corresponding asymmetric current versus voltage curves [22]. Herein, we focus on assessing the electrical characteristics of MIS based diodes fabricated completely by inkjet printing technology.…”

“…The complete layer stack consists of: (a) top and bottom printed conductive layers using a silver nano-particle ink and in other case PEDOT:PSS, (b) a polymeric insulator layer using poly (methylmethacrylate-methacrylic acid in ethtyl lactate) MMAcoMAA and (c) a polymeric polytriarylamine PTAA semiconducting layer. Due to the interaction between the MMAcoMAA and the semiconductor a MIS diode is obtained showing a rectifying behaviour [22]. Moreover, the yield of the MIS diode devices will be studied to ensure a reliable technology.…”