Journal article · Preprint article
Fermi Level Depinning in Two-Dimensional Materials Using a Fluorinated Bilayer Graphene Barrier
Strong Fermi level pinning (FLP), often attributed to metal-induced gap states at the interfacial contacts, severely reduces the tunability of the Schottky barrier height of the junction and limits applications of two-dimensional (2D) materials in electronics and optoelectronics. Here, we show that fluorinated bilayer graphene (FBLG) can be used as a barrier to effectively prevent FLP at metal/2D material interfaces.
FLBG can be produced via short exposure (1-3 min) to SF6 plasma that fluorinates only the top layer of a bilayer graphene with covalent C-F bonding, while the bottom layer remains intrinsic, resulting in a band gap opening of about 75 meV. Inserting FBLG between the metallic contacts and a layer of MoS2 reduces the Schottky barrier height dramatically for the low-work function metals (313 and 260 meV for Ti and Cr, respectively) while it increases for the high-work function one (160 meV for Pd), corresponding to an improved pinning factor.
Our results provide a straightforward method to generate atomically thin dielectrics with applications not only for depinning the Fermi level at metal/transition metal dichalcogenide interfaces but also for solving many other problems in electronics and optoelectronics.
Language: | English |
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Publisher: | American Chemical Society |
Year: | 2022 |
Pages: | 3955-3961 |
ISSN: | 26376113 |
Types: | Journal article and Preprint article |
DOI: | 10.1021/acsaelm.2c00609 |
ORCIDs: | Xiang, Cheng , Booth, Timothy J. , Bøggild, Peter , Doan, Manh Ha and 0000-0002-1163-2498 |