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Crystallized Monolayer Semiconductor for Ohmic Contact Resistance, High Intrinsic Gain, and High Current Density
Author(s) -
Peng Boyu,
Cao Ke,
Lau Albert Ho Yuen,
Chen Ming,
Lu Yang,
Chan Paddy K. L.
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202002281
Subject(s) - materials science , contact resistance , ohmic contact , optoelectronics , thermionic emission , monolayer , semiconductor , schottky barrier , organic semiconductor , transistor , saturation current , nanotechnology , field effect transistor , saturation (graph theory) , organic electronics , electrical engineering , layer (electronics) , voltage , diode , physics , mathematics , engineering , quantum mechanics , combinatorics , electron
The contact resistance limits the downscaling and operating range of organic field‐effect transistors (OFETs). Access resistance through multilayers of molecules and the nonideal metal/semiconductor interface are two major bottlenecks preventing the lowering of the contact resistance. In this work, monolayer (1L) organic crystals and nondestructive electrodes are utilized to overcome the abovementioned challenges. High intrinsic mobility of 12.5 cm 2 V −1 s −1 and Ohmic contact resistance of 40 Ω cm are achieved. Unlike the thermionic emission in common Schottky contacts, the carriers are predominantly injected by field emission. The 1L‐OFETs can operate linearly from V DS = −1 V to V DS as small as −0.1 mV. Thanks to the good pinch‐off behavior brought by the monolayer semiconductor, the 1L‐OFETs show high intrinsic gain at the saturation regime. At a high bias load, a maximum current density of 4.2 µA µm −1 is achieved by the only molecular layer as the active channel, with a current saturation effect being observed. In addition to the low contact resistance and high‐resolution lithography, it is suggested that the thermal management of high‐mobility OFETs will be the next major challenge in achieving high‐speed densely integrated flexible electronics.