Abstract The performance of electronic and optoelectronic devices is dominated by charge carrier injection through the metal–semiconductor contacts. Therefore, creating low-resistance electrical contacts is one of the most critical challenges in the development of devices based on new materials, particularly in the case of two-dimensional semiconductors. Herein, we report a strategy to reduce the contact resistance of MoS 2 via local pressurization. We fabricated electrical contacts using an atomic force microscopy tip and applied variable pressure ranging from 0 to 25 GPa. By measuring the transverse electronic transport properties, we show that MoS 2 undergoes a reversible semiconducting-metallic transition under pressure. Planar devices in field effect configuration with electrical contacts performed at pressures above ∼15 GPa show up to 30-fold reduced contact resistance and up to 25-fold improved field-effect mobility when compared to those measured at low pressure. Theoretical simulations show that this enhanced performance is due to improved charge injection to the MoS 2 semiconductor channel through the metallic MoS 2 phase obtained by pressurization. Our results suggest a novel strategy for realizing improved contacts to MoS 2 devices by local pressurization and for exploring emergent phenomena under mechano-electric modulation.
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Contact Engineering of Layered MoS 2 via Chemically Dipping Treatments
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 MoS2is demonstrated using a two‐step chemical treatment, (NH4)2S(aq) treatment and vacuum annealing, to enhance the contact behavior of metal/MoS2interfaces. The two‐step treatment induces changes in the contact of single layer MoS2field 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
- PAR ID:
- 10457970
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 30
- Issue:
- 16
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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