Growth Behavior of Ni on Hydrogen-Etched WS₂ Surface

Area of Science:

• Materials Science
• Surface Science
• Condensed Matter Physics

Background:

• Transition metal dichalcogenides (TMDs) are promising 2D materials for electronics.
• Poor adhesion between metals and TMDs hinders uniform electrode formation.
• Low adhesion forces limit the electronic applications of TMDs.

Purpose of the Study:

• To improve metal electrode quality on TMDs.
• To investigate the effect of atomic hydrogen (H) on WS2 surface.
• To optimize metal-TMD interfaces for enhanced electronic properties.

Main Methods:

• Utilized scanning tunneling microscopy (STM) for surface analysis.
• Employed synchrotron-based X-ray photoemission (XPS) for chemical state investigation.
• Introduced atomic H to create controlled surface defects on WS2.

Main Results:

• Atomic H created point defects at a density of ~3.05 × 10^11 cm^-2.
• Nickel (Ni) growth mode shifted from Volmer-Weber to near Frank-van der Merwe.
• Observed bond formation between Ni and Tungsten (W) atoms, indicating potential for ohmic contact.

Conclusions:

• Surface defect engineering with atomic H significantly enhances metal adhesion on TMDs.
• Optimized Ni growth on WS2 via defect creation facilitates ohmic contact.
• Findings provide insights for fabricating high-quality metal electrodes on 2D materials for electronic devices.