High Mobility WS2 Transistors Realized by Multilayer Graphene Electrodes and Application to High Responsivity Flexible Photodetectors

Adha Sukma Aji, Pablo Solís-Fernández, Hyun Goo Ji, Kenjiro Fukuda, Hiroki Ago

Research output: Contribution to journalArticlepeer-review

60 Citations (Scopus)


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 WS2 field-effect transistors. The gate-tunable Fermi level, van der Waals interaction with the WS2, and the high electrical conductivity of MLG significantly improve the overall performance of the devices. The carrier mobility of single-layer WS2 increases about a tenfold (50 cm2 V−1 s−1 at room temperature) by replacing conventional Ti/Au metal electrodes (5 cm2 V−1 s−1) with the MLG electrodes. Further, by replacing the conventional SiO2 substrate with a thin (1 µm) parylene-C flexible film as insulator, flexible WS2 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 WS2, graphene, and the very thin polymer film will find applications in various flexible electronics, such as wearable high-performance optoelectronics devices.

Original languageEnglish
Article number1703448
JournalAdvanced Functional Materials
Issue number47
Publication statusPublished - Dec 15 2017

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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