OECT as a Device for Material Characterization: the Role of Parasitic Series Resistance

abstract

English

The organic electrochemical transistor (OECT) is finding increasing application in the field of bioelectronics and material characterization. Due to the relatively wide range of applications, the requirements for this device are diverse. Some applications require fast response, while others require high sensitivity and therefore a low signal-to-noise ratio. In the case of sensing applications, mainly high sensitivity is required. the sensitivity of the device can be characterized by the transconductance value, which is calculated from the transfer characteristics. the transfer characteristics are measured as the dependence of the output current on the applied voltage at the gate electrode. Based on the obtained values of the transconductance and the parameters of the active OECT channel, also other parameters related to the used semiconducting material can be determined. Those parameters are used to benchmark organic semiconductor materials. This is based on the dependence of transconductance on channel length, width and thickness (Wd/L). However, when this dependence is plot for short-channel OECT (large ratio of Wd/L) the dependence decline from the expected linearity with increasing Wd/L ratio. That means some other parameters are involved, e.g. contact resistance or series resistance. In order to study the effect of contact and series resistance, the OECTs with different channel length and thickness (with different ratio of Wd/L) were prepared. the poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was used as the active channel material. From the transfer characteristics the peak transconductance value was calculated for each OECT, then the corrected transconductance value were calculated based on Antoniadis and Chou model. These corrected values could largely describe the observed deviation from the expected linearity. the results suggests that the serial resistance is the main factor worsening the sensitivity of the studied OECT devices.

OECT, PEDOT:PSS, conductivity, contact resistance, series resistance, transconductance, organic semiconductor

MARKOVÁ, A.; STŘÍTESKÝ, S.; WEITER, M.; VALA, M.

26. 11. 2020

Vysoké učení technické v Brně, Fakulta chemická

Brno

978-80-214-5920-0

Sborník abstraktů

1

102

103

2

https://www.fch.vut.cz/vav/konference/sok/vystupy/sbornik-abstrakty-konference-2020-pdf-p198641