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High Mobility WS 2 Transistors Realized by Multilayer Graphene Electrodes and Application to High Responsivity Flexible Photodetectors
Author(s) -
Aji Adha Sukma,
SolísFernández Pablo,
Ji Hyun Goo,
Fukuda Kenjiro,
Ago Hiroki
Publication year - 2017
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201703448
Subject(s) - materials science , optoelectronics , responsivity , graphene , photodetector , electrode , flexible electronics , parylene , thin film transistor , transistor , substrate (aquarium) , chemical vapor deposition , specific detectivity , thin film , electron mobility , field effect transistor , electronics , nanotechnology , layer (electronics) , polymer , composite material , electrical engineering , voltage , chemistry , oceanography , engineering , geology
The electrical contact is one of the main issues preventing semiconducting 2D materials to fulfill their potential in electronic and optoelectronic devices. To overcome this problem, a new approach is developed here that uses chemical vapor deposition grown multilayer graphene (MLG) sheets as flexible electrodes for WS 2 field‐effect transistors. The gate‐tunable Fermi level, van der Waals interaction with the WS 2 , and the high electrical conductivity of MLG significantly improve the overall performance of the devices. The carrier mobility of single‐layer WS 2 increases about a tenfold (50 cm 2 V −1 s −1 at room temperature) by replacing conventional Ti/Au metal electrodes (5 cm 2 V −1 s −1 ) with the MLG electrodes. Further, by replacing the conventional SiO 2 substrate with a thin (1 µm) parylene‐C flexible film as insulator, flexible WS 2 photodetectors that are able to sustain multiple bending stress tests without significant performance degradation are realized. The flexible photodetectors exhibited extraordinarily high gate‐tunable photoresponsivities, reaching values of 4500 A W −1 , and with very short (<2 ms) response time. The work of the heterostacked structure combining WS 2 , graphene, and the very thin polymer film will find applications in various flexible electronics, such as wearable high‐performance optoelectronics devices.