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Ohmic contact engineering in few-layer black phosphorus: approaching the quantum limit
F Telesio1, G le Gal1, M Serrano-Ruiz2
1NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy.
Nanotechnology
|April 25, 2020
Summary
Nickel contacts offer the lowest and most consistent resistance to black phosphorus (bP) field-effect transistors. This research provides crucial insights for optimizing Ohmic contacts in van der Waals materials.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Ohmic contacts to van der Waals materials are difficult due to interface energy barriers and material metallization.
- Black phosphorus (bP) is highly sensitive to oxidation, complicating contact fabrication and performance.
Purpose of the Study:
- To evaluate chromium, titanium, and nickel as contact metals for black phosphorus.
- To assess the impact of these metals on contact resistance variability in bP devices.
Main Methods:
- Fabrication of field-effect transistors using bP with different metal contacts.
- Analysis of gate-dependent current-voltage characteristics.
- Application of the transfer length method for contact resistance extraction.
Main Results:
- All investigated metals showed good linearity in the accumulation regime.
- Nickel (Ni) demonstrated the lowest contact resistance and minimal device-to-device variation.
- The best devices with Ni and Ti contacts approached the quantum limit of contact resistance.
Conclusions:
- Nickel is the preferred metal for achieving high-quality Ohmic contacts to black phosphorus.
- The findings are vital for advancing the performance and reliability of bP-based electronic devices.
