Contact Engineering of Layered MoS2 via Chemically Dipping Treatments
Abstract
The performance of electronic/optoelectronic devices is governed by carrier injection through metal–semiconductor contact; therefore, it is crucial to employ low‐resistance source/drain contacts. However, unintentional introduction of extrinsic defects, such as substoichiometric oxidation states at the metal–semiconductor interface, can degrade carrier injection. In this report, controlling the unintentional extrinsic defect states in layered MoS2 is demonstrated using a two‐step chemical treatment, (NH4)2S(aq) treatment and vacuum annealing, to enhance the contact behavior of metal/MoS2 interfaces. The two‐step treatment induces changes in the contact of single layer MoS2 field effect transistors from nonlinear Schottky to Ohmic behavior, along with a reduction of contact resistance from 35.2 to 5.2 kΩ. Moreover, the enhancement of ION and electron field effect mobility of single layer MoS2 field effect transistors is nearly double for n‐branch operation. This enhanced contact behavior resulting from the two‐step treatment is likely due to the removal of oxidation defects, which can be unintentionally introduced during synthesis or fabrication processes. The removal of oxygen defects is confirmed by scanning tunneling microscopy and X‐ray photoelectron spectroscopy. This two‐step (NH4)2S(aq) chemical functionalization process provides a facile pathway to controlling the defect states in transition metal dichalcogenides (TMDs), to enhance the metal‐contact behavior of TMDs.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 25, 2020
- Source ID
- 10.1002/adfm.202000250
Entities
People
- Amritesh Rai
- Andrew C Kummel
- Choong‐heui Chung
- Iljo Kawk
- Jun Hong Park
- Mun Seok Jeong
- Ngoc Thanh Duong
- Sangyeob Lee
- Sanjay K. Banerjee
- Seungho Bang
- Steven Wolf
Organizations
- Defense Advanced Research Projects Agency
- Gyeongsang National University
- Hanbat National University
- National Research Foundation of Korea
- National Science Foundation
- Sungkyunkwan University
- University of California, San Diego
- University of Texas at Austin