Eliminating the Double-Slope Behavior of Organic Field-Effect Transistors by Functionalizing the Dielectric Surface With a High Electron Affinity Self-Assembly Monolayer

• Published in: IEEE transactions on electron devices Vol. 71; no. 1; pp. 777 - 781
• Main Authors: Hu, Yuanhong, Fu, Huaijie, Zhang, Qiaoming, Peng, Jinlei, Wei, Jiyuan, Tan, Xingwen, Qiu, Xuejun, Lei, Yanlian
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Affinity; Behavioral sciences; Carrier mobility; Contact resistance; Dielectrics; Display devices; Double-slope behavior; Electron affinity; Electron traps; Field effect transistors; Hysteresis; Monolayers; OFETs; organic field-effect transistor (OFET); Self-assembled monolayers; Self-assembly; self-assembly monolayer; Semiconductor devices; Surface morphology; Transistors
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2023.3338152

The commonly observed nonideal behavior (namely double-slope) in transfer characteristics of organic field-effect transistors (OFETs) is detrimental to the accurate assessment of carrier mobility. In this work, self-assembled monolayers (SAMs) with different end groups were used to adjust the electron affinity of dielectric surfaces to eliminate the double-slope behavior of OFETs. Results show that the OFETs based on the SAM with a high electron affinity end group of -CN (hereafter named SAM-CN device) display an ideal transfer curve without double-slope behavior and hysteresis. A series of cross-checks, including contact resistance and time-dependent measurements, have been carried out to experimentally confirm that electron traps at the channel/dielectric interface are the origin of double-slope behavior. Furthermore, the suppression of double-slope behavior in SAM-CN devices is attributed to the high electron affinity of the -CN group to withdraw electrons from the trap sites located at the conducting channel. Thus, our results provide an easy and feasible strategy to eliminate the double-slope behavior of OFETs by using a SAM with an appropriate electron affinity.