Open AccessThe Origin of Low Contact Resistance in Monolayer Organic Field‐Effect Transistors with van der Waals Electrodes
Author(s) -
Chen Ming,
Peng Boyu,
Sporea Radu A.,
Podzorov Vitaly,
Chan Paddy Kwok Leung
Publication year - 2022
Publication title -
small science
Language(s) - English
Resource type - Journals
ISSN - 2688-4046
DOI - 10.1002/smsc.202100115
Subject(s) - contact resistance , monolayer , materials science , organic semiconductor , optoelectronics , field effect transistor , organic electronics , schottky barrier , organic field effect transistor , transistor , equivalent series resistance , schottky diode , nanotechnology , diode , voltage , electrical engineering , layer (electronics) , engineering
The successful commercialization of organic field‐effect transistors (OFETs) for advanced integrated organic electronics requires reducing device sizes, which inevitably clashes with the constraints imposed by the contact effects. Herein, it is demonstrated that the contact resistance in OFETs based on monolayer organic semiconductors is extremely low, especially at mild biasing conditions. The contributions of the access resistance and the metal–organic interface resistance are successfully disentangled for the first time. It is shown that, contrary to the conventional view, the contact resistance of monolayer OFETs in the saturation regime exhibits a very weak dependence on the source electrode length. In the monolayer OFETs based on 2,9‐didecyldinaphtho[2,3‐b:2’,3’‐f]thieno[3,2‐b]thiophene (C 10 ‐DNTT), a gate‐voltage‐independent access resistivity (2.2 × 10 −2 Ω cm 2 ) at V DS = −1 mV is obtained, while the interfacial metal–organic Schottky contact resistance is found to be negligible. The depletion of a diode associated with the metal–organic interface expands with increasing V DS and eventually bottlenecks the device performance. Finally, how to overcome such a carrier depletion contact resistance bottleneck and achieve OFETs with outstanding performance are shown. These findings pave the way toward sophisticated organic electronic applications based on the use of monolayer OFETs.