Low Resistance Contact to P-Type Monolayer WSe2

Jingxu Xie; Zuocheng Zhang; Haodong Zhang; Vikram Nagarajan; Wenyu Zhao; Ha-Leem Kim; Collin Sanborn; Ruishi Qi; Sudi Chen; Salman Kahn; Kenji Watanabe; Takashi Taniguchi; Alex Zettl; Michael F Crommie; James Analytis; Feng Wang

doi:10.1021/acs.nanolett.3c04195

Low Resistance Contact to P-Type Monolayer WSe₂

Nano Lett. 2024 May 22;24(20):5937-5943. doi: 10.1021/acs.nanolett.3c04195. Epub 2024 May 7.

Authors

Jingxu Xie^{1

2

3}, Zuocheng Zhang¹, Haodong Zhang¹, Vikram Nagarajan¹, Wenyu Zhao¹, Ha-Leem Kim^{1

3}, Collin Sanborn¹, Ruishi Qi^{1

3}, Sudi Chen¹, Salman Kahn¹, Kenji Watanabe⁴, Takashi Taniguchi⁵, Alex Zettl^{1

3

6}, Michael F Crommie^{1

3

6}, James Analytis^{1

3

6}, Feng Wang^{1

3

6}

Affiliations

¹ Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States.
² Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, California 94720, United States.
³ Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
⁴ Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
⁵ Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
⁶ Kavli Energy NanoSciences Institute at University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.

PMID: 38712885
DOI: 10.1021/acs.nanolett.3c04195

Abstract

Advanced microelectronics in the future may require semiconducting channel materials beyond silicon. Two-dimensional (2D) semiconductors, with their atomically thin thickness, hold great promise for future electronic devices. One challenge to achieving high-performance 2D semiconductor field effect transistors (FET) is the high contact resistance at the metal-semiconductor interface. In this study, we develop a charge-transfer doping strategy with WSe₂/α-RuCl₃ heterostructures to achieve low-resistance ohmic contact for p-type monolayer WSe₂ transistors. We show that hole doping as high as 3 × 10¹³ cm^-2 can be achieved in the WSe₂/α-RuCl₃ heterostructure due to its type-III band alignment, resulting in an ohmic contact with resistance of 4 kΩ μm. Based on that, we demonstrate p-type WSe₂ transistors with an on-current of 35 μA·μm^-1 and an I_ON/I_OFF ratio exceeding 10⁹ at room temperature.

Keywords: charge transfer; ohmic contacts; p-type monolayer WSe2 FET; type-III band alignment; α-RuCl3.