ZrTe₂ Compound Dirac Semimetal Contacts for High-Performance MoS₂ Transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Conventional fabrication methods for 2D semiconductor contacts face challenges in approaching the quantum limit.
• Elemental semimetals like Bismuth (Bi) and Antimony (Sb) show promise but have limitations.
• The need for optimal contact solutions is critical for advancing 2D semiconductor electronics.

Purpose of the Study:

• To demonstrate novel compound Dirac semimetal zirconium telluride (ZrTe2) as contacts for 2D semiconductors.
• To investigate the contact characteristics and performance of ZrTe2 contacts on Molybdenum disulfide (MoS2).
• To explore the potential of 2D compound semimetals for next-generation electronics.

Main Methods:

• Fabrication of ZrTe2 contacts on MoS2 using a nondestructive van der Waals (vdW) transfer process.
• Characterization of contact properties, including Schottky barrier height and band hybridization.
• Fabrication and testing of bilayer MoS2 transistors with ZrTe2 contacts on hexagonal boron nitride (h-BN) substrates.

Main Results:

• ZrTe2 contacts exhibited excellent ohmic contact characteristics with a negligible Schottky barrier.
• Verified band hybridization between the ZrTe2 contact and the MoS2 channel.
• Bilayer MoS2 transistors demonstrated a high on/off current ratio (>10^5) and significant on-state current (259 μA μm^-1).

Conclusions:

• 2D compound semimetals, specifically ZrTe2, offer a viable solution for high-performance 2D semiconductor contacts.
• Van der Waals contacts with compound semimetals provide tunable work functions for diverse electronic applications.
• This approach paves the way for advanced 2D-based electronics beyond current silicon limitations.