Stable operation of water-gated organic field-effect transistor depending on channel flatness, electrode metals and surface treatment

• Published in: Japanese Journal of Applied Physics Vol. 58; no. SD; p. SDDH02
• Main Authors: Nguy, Tin Phan, Hayakawa, Ryoma, Kilinc, Volkan, Petit, Matthieu, Raimundo, Jean-Manuel, Charrier, Anne, Wakayama, Yutaka
• Format: Journal Article
• Language: English
• Published: Tokyo IOP Publishing 01.06.2019; Japanese Journal of Applied Physics; Japan Society of Applied Physics
• Subjects: Carrier traps; Condensed Matter; Electrodes; Engineering Sciences; Field effect transistors; Flat surfaces; Gold; Hysteresis loops; Lipids; Materials Science; Micro and nanotechnologies; Microelectronics; Morphology; Physics; Semiconductor devices; Surface treatment; Threshold voltage; Transistors
• ISSN: 0021-4922; 1347-4065
• DOI: 10.7567/1347-4065/ab09d2

The main purpose of this study is to clarify the factors for the stable operation of a poly(3-hexylthiophene) (P3HT)-based water gated organic field effect transistor (WG-OFET). To this end, the influence of the surface morphologies and electrode metals on the transistor properties were investigated. The experimental results indicated that a flat surface improved the on/off ratio and switching repeatability. Treating the surface with a lipid membrane was found to reduce hysteresis loops in the transfer curves probably due to the reduced number of carrier traps. The Au gate electrode effectively lowered the threshold voltage. Consequently, stable transistor operation with a low threshold voltage of 35 mV was achieved by employing a gold gate electrode and lipid membrane treatment. These results suggest that WG-OFETs with an ultra-thin lipid membrane have great potential for sensor applications, and in particular for sensing water-soluble analytes.