Self-Intercalation Metallization Enables Low-Resistance Contacts in ZrSe₂ and HfSe₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides like ZrSe2 and HfSe2 are promising for post-silicon electronics.
• Their performance is currently limited by high contact resistance, hindering practical applications.

Purpose of the Study:

• To develop a novel metallization strategy for 2D ZrSe2 and HfSe2.
• To overcome the challenge of high contact resistance in these materials.
• To improve the performance of devices based on 2D ZrSe2 and HfSe2.

Main Methods:

• A self-intercalation metallization strategy was employed.
• Excess Zr and Hf atoms were inserted into the van der Waals (vdW) gaps of 2D materials.
• This induced a semiconductor-to-metal transition and expanded the vdW gaps.

Main Results:

• The process created metallic buffers with significantly reduced contact resistance (>100x lower than Au).
• Devices showed low Schottky barriers (~27 meV) and high on/off ratios (up to 10^4).
• A >20x increase in on-current was observed compared to devices with Au contacts.

Conclusions:

• The self-intercalation method successfully establishes a low-barrier contact paradigm for Zr/Hf selenides.
• This technique offers a general approach for contact engineering in emerging 2D semiconductors.
• The findings pave the way for high-performance postsilicon electronic devices.