Origins of genuine Ohmic van der Waals contact between indium and MoS2

Abstract The achievement of ultraclean Ohmic van der Waals (vdW) contacts at metal/transition-metal dichalcogenide (TMDC) interfaces would represent a critical step for the development of high-performance electronic and optoelectronic devices based on two-dimensional (2D) semiconductors. Herein, we...

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Autores principales:	Bum-Kyu Kim, Tae-Hyung Kim, Dong-Hwan Choi, Hanul Kim, Kenji Watanabe, Takashi Taniguchi, Heesuk Rho, Ju-Jin Kim, Yong-Hoon Kim, Myung-Ho Bae
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Materials of engineering and construction. Mechanics of materials TA401-492 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/28ece4a7e7f6451c9adee24c084ccb74
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spelling	oai:doaj.org-article:28ece4a7e7f6451c9adee24c084ccb742021-12-02T13:35:39ZOrigins of genuine Ohmic van der Waals contact between indium and MoS210.1038/s41699-020-00191-z2397-7132https://doaj.org/article/28ece4a7e7f6451c9adee24c084ccb742021-01-01T00:00:00Zhttps://doi.org/10.1038/s41699-020-00191-zhttps://doaj.org/toc/2397-7132Abstract The achievement of ultraclean Ohmic van der Waals (vdW) contacts at metal/transition-metal dichalcogenide (TMDC) interfaces would represent a critical step for the development of high-performance electronic and optoelectronic devices based on two-dimensional (2D) semiconductors. Herein, we report the fabrication of ultraclean vdW contacts between indium (In) and molybdenum disulfide (MoS2) and the clarification of the atomistic origins of its Ohmic-like transport properties. Atomically clean In/MoS2 vdW contacts are achieved by evaporating In with a relatively low thermal energy and subsequently cooling the substrate holder down to ~100 K by liquid nitrogen. We reveal that the high-quality In/MoS2 vdW contacts are characterized by a small interfacial charge transfer and the Ohmic-like transport based on the field-emission mechanism over a wide temperature range from 2.4 to 300 K. Accordingly, the contact resistance reaches ~600 Ω μm and ~1000 Ω μm at cryogenic temperatures for the few-layer and monolayer MoS2 cases, respectively. Density functional calculations show that the formation of large in-gap states due to the hybridization between In and MoS2 conduction band edge states is the microscopic origins of the Ohmic charge injection. We suggest that seeking a mechanism to generate strong density of in-gap states while maintaining the pristine contact geometry with marginal interfacial charge transfer could be a general strategy to simultaneously avoid Fermi-level pinning and minimize contact resistance for 2D vdW materials.Bum-Kyu KimTae-Hyung KimDong-Hwan ChoiHanul KimKenji WatanabeTakashi TaniguchiHeesuk RhoJu-Jin KimYong-Hoon KimMyung-Ho BaeNature PortfolioarticleMaterials of engineering and construction. Mechanics of materialsTA401-492ChemistryQD1-999ENnpj 2D Materials and Applications, Vol 5, Iss 1, Pp 1-10 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Materials of engineering and construction. Mechanics of materials TA401-492 Chemistry QD1-999
spellingShingle	Materials of engineering and construction. Mechanics of materials TA401-492 Chemistry QD1-999 Bum-Kyu Kim Tae-Hyung Kim Dong-Hwan Choi Hanul Kim Kenji Watanabe Takashi Taniguchi Heesuk Rho Ju-Jin Kim Yong-Hoon Kim Myung-Ho Bae Origins of genuine Ohmic van der Waals contact between indium and MoS2
description	Abstract The achievement of ultraclean Ohmic van der Waals (vdW) contacts at metal/transition-metal dichalcogenide (TMDC) interfaces would represent a critical step for the development of high-performance electronic and optoelectronic devices based on two-dimensional (2D) semiconductors. Herein, we report the fabrication of ultraclean vdW contacts between indium (In) and molybdenum disulfide (MoS2) and the clarification of the atomistic origins of its Ohmic-like transport properties. Atomically clean In/MoS2 vdW contacts are achieved by evaporating In with a relatively low thermal energy and subsequently cooling the substrate holder down to ~100 K by liquid nitrogen. We reveal that the high-quality In/MoS2 vdW contacts are characterized by a small interfacial charge transfer and the Ohmic-like transport based on the field-emission mechanism over a wide temperature range from 2.4 to 300 K. Accordingly, the contact resistance reaches ~600 Ω μm and ~1000 Ω μm at cryogenic temperatures for the few-layer and monolayer MoS2 cases, respectively. Density functional calculations show that the formation of large in-gap states due to the hybridization between In and MoS2 conduction band edge states is the microscopic origins of the Ohmic charge injection. We suggest that seeking a mechanism to generate strong density of in-gap states while maintaining the pristine contact geometry with marginal interfacial charge transfer could be a general strategy to simultaneously avoid Fermi-level pinning and minimize contact resistance for 2D vdW materials.
format	article
author	Bum-Kyu Kim Tae-Hyung Kim Dong-Hwan Choi Hanul Kim Kenji Watanabe Takashi Taniguchi Heesuk Rho Ju-Jin Kim Yong-Hoon Kim Myung-Ho Bae
author_facet	Bum-Kyu Kim Tae-Hyung Kim Dong-Hwan Choi Hanul Kim Kenji Watanabe Takashi Taniguchi Heesuk Rho Ju-Jin Kim Yong-Hoon Kim Myung-Ho Bae
author_sort	Bum-Kyu Kim
title	Origins of genuine Ohmic van der Waals contact between indium and MoS2
title_short	Origins of genuine Ohmic van der Waals contact between indium and MoS2
title_full	Origins of genuine Ohmic van der Waals contact between indium and MoS2
title_fullStr	Origins of genuine Ohmic van der Waals contact between indium and MoS2
title_full_unstemmed	Origins of genuine Ohmic van der Waals contact between indium and MoS2
title_sort	origins of genuine ohmic van der waals contact between indium and mos2
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/28ece4a7e7f6451c9adee24c084ccb74
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Origins of genuine Ohmic van der Waals contact between indium and MoS2

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