Characterization of organic field effect transistors for OLED displays

Abstract

This thesis explores the characterization of OFETs that will aid the circuit design of OLED pixel drivers. The contact resistance, flat band voltage, and mobility are extracted from top contact and bottom contact transistors with current-voltage (I-V) and low frequency capacitance-voltage (C-V) measurements. Extraction of contact resistance is found to be crucial in characterization of bottom-contact transistors as it obscures mobility extraction. An unambiguous method of extracting flat band voltage is explored and mobility is extracted with minimal assumptions by separation of charge and mobility from C-V measurements. Mobility is found to increase with gate voltage differing significantly from mobility dependence in crystal silicon MOSFETs.