Anisotropic charge transport at the metallic edge contact of ReS2 field effect transistors

Hyokwang Park; Myeongjin Lee; Xinbiao Wang; Nasir Ali; Kenji Watanabe; Takashi Taniguchi; Euyheon Hwang; Won Jong Yoo

doi:10.1038/s43246-024-00526-z

Article Anisotropic charge transport at the metallic edge contact of ReS2 field effect transistors

Hyokwang Park ; Myeongjin Lee ; Xinbiao Wang ; Nasir Ali ; Kenji Watanabe (National Institute for Materials Science) ; Takashi Taniguchi (National Institute for Materials Science) ; Euyheon Hwang ; Won Jong Yoo

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Hyokwang Park, Myeongjin Lee, Xinbiao Wang, Nasir Ali, Kenji Watanabe, Takashi Taniguchi, Euyheon Hwang, Won Jong Yoo. Anisotropic charge transport at the metallic edge contact of ReS2 field effect transistors. Communications Materials. 2024, 5 (1), 87. https://doi.org/10.1038/s43246-024-00526-z

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The in-plane anisotropy of electrical conductance in two-dimensional (2D) materials has garnered significant attention due to its potential in emerging device applications, offering an additional dimension to control carrier transport in 2D devices. However, previous research has primarily focused on the anisotropy within the electrical channel, neglecting the significant impact of anisotropic electrical contacts of 2D materials. Here, we investigate anisotropic charge transport at the metal contacts of hBN-encapsulated ReS2 using edge-contacted FETs. We observed the marked difference in contact resistance between the cross-b and b directions, suggesting that charge transport from the metal to ReS2 is significantly more efficient along the b direction. This difference in efficiency results in a substantial contact anisotropy, reaching ~ 70 at 77K. Our findings indicate that the measured SBH along the b direction is ~ 35 meV, which is smaller than along the cross-b direction. Moreover, the tunneling probability along the b direction is two timeslarger than along the cross-b direction. Our results indicate that both SBH and tunneling amplitude are the primary contributors to the high contact anisotropy of ReS2. This work provides a valuable guideline for understanding how in-plane orientation influences charge transport at metallic contacts in 2D devices.

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