Improved Contact Resistance by a Single Atomic Layer Tunneling Effect in WS2/MoTe2 Heterostructures. Issue 11 (15th March 2021)

• Record Type: Journal Article
• Authors: Kim, Jihoon; Venkatesan, A.; Kim, Hanul; Kim, Yewon; Whang, Dongmok; Kim, Gil‐Ho
• Is Part Of: Advanced science. Volume 8:Issue 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-15
• Subjects: contact resistance -- monolayer -- tunneling -- vdW heterostructures -- WS2/MoTe2; Science -- Periodicals; 505
• DOI: 10.1002/advs.202100102
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: Manipulation of Ohmic contacts in 2D transition metal dichalcogenides for enhancing the transport properties and enabling its application as a practical device has been a long‐sought goal. In this study, n‐type tungsten disulfide (WS2 ) single atomic layer to improve the Ohmic contacts of the p‐type molybdenum ditelluride (MoTe2 ) material is covered. The Ohmic properties, based on the lowering of Schottky barrier height (SBH) owing to the tunneling barrier effect of the WS2 monolayer, are found to be unexpectedly excellent at room temperature and even at 100 K. The improved SBH and contact resistances are 3 meV and 1 MΩ µm, respectively. The reduction in SBH and contact resistance is confirmed with temperature‐dependent transport measurements. This study further demonstrates the selective carrier transport across the MoTe2 and WS2 layers by modulating the applied gate voltage. This WS2 /MoTe2 heterostructure exhibits excellent gate control over the currents of both channels (n‐type and p‐type). The on/off ratios for both the electron and hole channels are calculated as 10 7 and 10 6, respectively, indicating good carrier type modulation by the electric field of the gate electrode. The Ohmic contact resistance using the tunneling of the atomic layer can be applied to heterojunction combinations of various materials. Abstract : Innovative heterostructure consisting of a semiconducting monolayer WS2 tunneling layer and a few‐layer bottom MoTe2 is reported. By applying an appropriate gate voltage, n‐channel in WS2 monolayer and p‐channel in MoTe2 are accessed separately. Owing to single atomic thickness of WS2, the Schottky barrier and contact resistance on few‐layer MoTe2 are greatly reduced resulting in good Ohmic contact.