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Title: Mechanism of Fermi Level Pinning for Metal Contacts on Molybdenum Dichalcogenide
The high contact resistance of transition metal dichalcogenide (TMD) -based devices is receiving considerable attention due to its limitation on electronic performance. The mechanism of Fermi level (EF) pinning, which causes the high contact resistance, is not thoroughly understood to date. In this study, the metal (Ni and Ag)/Mo-TMDs surfaces and interfaces are characterized by X-ray photoelectron spectroscopy, atomic force microscopy, scanning tunneling microscopy and spectroscopy, and density functional theory systematically. Ni and Ag form covalent and van der Waals (vdW) interfaces on Mo-TMDs, respectively. Imperfections are detected on Mo-TMDs, which leads to electronic and spatial variations. Gap states appear after the adsorption of single, and two metal atoms on Mo-TMDs. The combination of the interface reaction type (covalent or vdW), the imperfection variability of the TMD materials, and the gap states induced by contact metals with different weights are concluded to be the origins of EF pinning.  more » « less
Award ID(s):
2002741
PAR ID:
10520950
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
ACS Applied Materials & Interfaces
Volume:
16
Issue:
10
ISSN:
1944-8244
Page Range / eLocation ID:
13258 to 13266
Subject(s) / Keyword(s):
transition metal dichalcogenide, metal contact, Fermi level pinning, interface chemistry, band alignment, surface imperfections, adsorption
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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