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High-Quality P-type Contacts for Atomically Thin MoTe2 Transistors with High-Work-Function Semimetal TiS2 Electrodes.
Boyuan Di1,2, Xinlu Li3, Xiaokun Wen1,2
1State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PRC.
ACS Applied Materials & Interfaces
|April 18, 2025
Summary
High-performance p-type atomically thin transistors are crucial for future electronics. Researchers developed high-quality contacts using titanium disulfide (TiS₂) for molybdenum ditelluride (MoTe₂) transistors, enhancing performance.
Area of Science:
- Materials Science
- Semiconductor Physics
- Nanotechnology
Background:
- High-performance p-type atomically thin transistors are essential for beyond-silicon CMOS digital logic.
- Achieving high-quality contacts for p-type transistors has been a significant challenge, unlike for n-type transistors.
- The lack of suitable high-work-function metallic electrodes with Fermi level unpinning capacity has hindered progress.
Purpose of the Study:
- To demonstrate semimetal TiS₂ as a feasible electrode material for high-performance p-type atomically thin MoTe₂ transistors.
- To overcome the limitations of existing electrode materials for p-type transistor applications.
- To enable monolithic atomically thin MoTe₂-based electronics using standard CMOS technology.
Main Methods:
- Utilizing semimetal TiS₂ as electrodes prepared via a damage-free transfer process.
- Fabricating p-type atomically thin MoTe₂ transistors with TiS₂ contacts.
- Characterizing the electrical performance of both bilayer and monolayer MoTe₂ transistors.
Main Results:
- TiS₂ electrodes exhibited a large work function (∼5.3 eV) and formed high-quality contacts with MoTe₂.
- Negligible Schottky barriers were observed at the TiS₂/MoTe₂ interface.
- Scaled p-type bilayer MoTe₂ transistors (500 nm channel) achieved I<0xE2><0x82><0x92><0xE2><0x82><0x99> of 100 μA/μm and I<0xE2><0x82><0x92><0xE2><0x82><0x99>/I<0xE2><0x82><0x92><0xE2><0x82><0x9F><0xE2><0x82><0x9F> > 10⁶.
- Monolayer MoTe₂ transistors (800 nm channel) achieved I<0xE2><0x82><0x92><0xE2><0x82><0x99> of 68 μA/μm and I<0xE2><0x82><0x92><0xE2><0x82><0x99>/I<0xE2><0x82><0x92><0xE2><0x82><0x9F><0xE2><0x82><0x9F> > 10⁷.
Conclusions:
- Semimetal TiS₂ is a viable solution for creating high-quality contacts in p-type atomically thin MoTe₂ transistors.
- The developed approach facilitates the integration of MoTe₂-based devices into CMOS technology.
- This breakthrough paves the way for advanced beyond-silicon electronics.
