Lowering the Schottky Barrier Height by Graphene/Ag Electrodes for High-Mobility MoS2 Field-Effect Transistors

Sang Soo Chee, Dongpyo Seo, Hanggyu Kim, Hanbyeol Jang, Seungmin Lee, Seung Pil Moon, Kyu Hyoung Lee, Sung Wng Kim, Hyunyong Choi, Moon Ho Ham

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

2D transition metal dichalcogenides (TMDCs) have emerged as promising candidates for post-silicon nanoelectronics owing to their unique and outstanding semiconducting properties. However, contact engineering for these materials to create high-performance devices while adapting for large-area fabrication is still in its nascent stages. In this study, graphene/Ag contacts are introduced into MoS2 devices, for which a graphene film synthesized by chemical vapor deposition (CVD) is inserted between a CVD-grown MoS2 film and a Ag electrode as an interfacial layer. The MoS2 field-effect transistors with graphene/Ag contacts show improved electrical and photoelectrical properties, achieving a field-effect mobility of 35 cm2 V−1 s−1, an on/off current ratio of 4 × 108, and a photoresponsivity of 2160 A W−1, compared to those of devices with conventional Ti/Au contacts. These improvements are attributed to the low work function of Ag and the tunability of graphene Fermi level; the n-doping of Ag in graphene decreases its Fermi level, thereby reducing the Schottky barrier height and contact resistance between the MoS2 and electrodes. This demonstration of contact interface engineering with CVD-grown MoS2 and graphene is a key step toward the practical application of atomically thin TMDC-based devices with low-resistance contacts for high-performance large-area electronics and optoelectronics.

Original languageEnglish
Article number1804422
JournalAdvanced Materials
Volume31
Issue number2
DOIs
Publication statusPublished - 2019 Jan 11

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Graphite
Field effect transistors
Graphene
Electrodes
Chemical vapor deposition
Contact resistance
Fermi level
Transition metals
Nanoelectronics
Silicon
Optoelectronic devices
Electronic equipment
Demonstrations
Doping (additives)
Fabrication

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Chee, Sang Soo ; Seo, Dongpyo ; Kim, Hanggyu ; Jang, Hanbyeol ; Lee, Seungmin ; Moon, Seung Pil ; Lee, Kyu Hyoung ; Kim, Sung Wng ; Choi, Hyunyong ; Ham, Moon Ho. / Lowering the Schottky Barrier Height by Graphene/Ag Electrodes for High-Mobility MoS2 Field-Effect Transistors. In: Advanced Materials. 2019 ; Vol. 31, No. 2.
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abstract = "2D transition metal dichalcogenides (TMDCs) have emerged as promising candidates for post-silicon nanoelectronics owing to their unique and outstanding semiconducting properties. However, contact engineering for these materials to create high-performance devices while adapting for large-area fabrication is still in its nascent stages. In this study, graphene/Ag contacts are introduced into MoS2 devices, for which a graphene film synthesized by chemical vapor deposition (CVD) is inserted between a CVD-grown MoS2 film and a Ag electrode as an interfacial layer. The MoS2 field-effect transistors with graphene/Ag contacts show improved electrical and photoelectrical properties, achieving a field-effect mobility of 35 cm2 V−1 s−1, an on/off current ratio of 4 × 108, and a photoresponsivity of 2160 A W−1, compared to those of devices with conventional Ti/Au contacts. These improvements are attributed to the low work function of Ag and the tunability of graphene Fermi level; the n-doping of Ag in graphene decreases its Fermi level, thereby reducing the Schottky barrier height and contact resistance between the MoS2 and electrodes. This demonstration of contact interface engineering with CVD-grown MoS2 and graphene is a key step toward the practical application of atomically thin TMDC-based devices with low-resistance contacts for high-performance large-area electronics and optoelectronics.",
author = "Chee, {Sang Soo} and Dongpyo Seo and Hanggyu Kim and Hanbyeol Jang and Seungmin Lee and Moon, {Seung Pil} and Lee, {Kyu Hyoung} and Kim, {Sung Wng} and Hyunyong Choi and Ham, {Moon Ho}",
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Chee, SS, Seo, D, Kim, H, Jang, H, Lee, S, Moon, SP, Lee, KH, Kim, SW, Choi, H & Ham, MH 2019, 'Lowering the Schottky Barrier Height by Graphene/Ag Electrodes for High-Mobility MoS2 Field-Effect Transistors', Advanced Materials, vol. 31, no. 2, 1804422. https://doi.org/10.1002/adma.201804422

Lowering the Schottky Barrier Height by Graphene/Ag Electrodes for High-Mobility MoS2 Field-Effect Transistors. / Chee, Sang Soo; Seo, Dongpyo; Kim, Hanggyu; Jang, Hanbyeol; Lee, Seungmin; Moon, Seung Pil; Lee, Kyu Hyoung; Kim, Sung Wng; Choi, Hyunyong; Ham, Moon Ho.

In: Advanced Materials, Vol. 31, No. 2, 1804422, 11.01.2019.

Research output: Contribution to journalArticle

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AU - Chee, Sang Soo

AU - Seo, Dongpyo

AU - Kim, Hanggyu

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AU - Lee, Seungmin

AU - Moon, Seung Pil

AU - Lee, Kyu Hyoung

AU - Kim, Sung Wng

AU - Choi, Hyunyong

AU - Ham, Moon Ho

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AB - 2D transition metal dichalcogenides (TMDCs) have emerged as promising candidates for post-silicon nanoelectronics owing to their unique and outstanding semiconducting properties. However, contact engineering for these materials to create high-performance devices while adapting for large-area fabrication is still in its nascent stages. In this study, graphene/Ag contacts are introduced into MoS2 devices, for which a graphene film synthesized by chemical vapor deposition (CVD) is inserted between a CVD-grown MoS2 film and a Ag electrode as an interfacial layer. The MoS2 field-effect transistors with graphene/Ag contacts show improved electrical and photoelectrical properties, achieving a field-effect mobility of 35 cm2 V−1 s−1, an on/off current ratio of 4 × 108, and a photoresponsivity of 2160 A W−1, compared to those of devices with conventional Ti/Au contacts. These improvements are attributed to the low work function of Ag and the tunability of graphene Fermi level; the n-doping of Ag in graphene decreases its Fermi level, thereby reducing the Schottky barrier height and contact resistance between the MoS2 and electrodes. This demonstration of contact interface engineering with CVD-grown MoS2 and graphene is a key step toward the practical application of atomically thin TMDC-based devices with low-resistance contacts for high-performance large-area electronics and optoelectronics.

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