US EPA

4750142 

Journal Article 

Low-Temperature Ohmic Contact to Monolayer MoS2 by van der Waals Bonded Co/h-BN Electrodes 

Cui, X; Shih, EM; Jauregui, LA; Chae, SH; Kim, YD; Li, B; Seo, D; Pistunova, K; Yin, J; Park, JH; Choi, HJ; Lee, YH; Watanabe, K; Taniguchi, T; Kim, P; Dean, CR; Hone, JC 

2017 

1 

Nano Letters
ISSN: 1530-6984
EISSN: 1530-6992 

17 

8 

4781-4786 

English 

28691487 

10.1021/acs.nanolett.7b01536 

WOS:000407540300034 

Monolayer MoS2, among many other transition metal dichalcogenides, holds great promise for future applications in nanoelectronics and optoelectronics due to its ultrathin nature, flexibility, sizable band gap, and unique spin-valley coupled physics. However, careful study of these properties at low temperature has been hindered by an inability to achieve low-temperature Ohmic contacts to monolayer MoS2, particularly at low carrier densities. In this work, we report a new contact scheme that utilizes cobalt (Co) with a monolayer of hexagonal boron nitride (h-BN) that has the following two functions: modifies the work function of Co and acts as a tunneling barrier. We measure a flat-band Schottky barrier of 16 meV, which makes thin tunnel barriers upon doping the channels, and thus achieve low-T contact resistance of 3 kΩ.μm at a carrier density of 5.3 × 1012/cm2. This further allows us to observe Shubnikov-de Haas oscillations in monolayer MoS2 at much lower carrier densities compared to previous work.