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Mixed-Dimensional Contact Architecture to WSe2 for Efficient Hole Injection.
Seungyun Lee1, Dongryul Lee1,2, Donggyu Lee1
1Department of Chemical and Biological Engineering, Seoul National University, Seoul 08826, Republic of Korea.
ACS Applied Materials & Interfaces
|April 18, 2025
Summary
Researchers developed a novel mixed-dimensional contact for tungsten diselenide (WSe2) transistors, significantly improving hole injection and device performance. This breakthrough addresses limitations in nanoscale electronics for next-generation applications.
Area of Science:
- Materials Science
- Nanotechnology
- Semiconductor Physics
Background:
- Silicon (Si)-based electronics face nanoscale limitations like short-channel effects.
- Transition-metal dichalcogenides (TMDs) offer advantages over Si, including dangling-bond-free surfaces and tunable bandgaps.
- Tungsten diselenide (WSe2) is a promising p-type semiconductor, but Fermi-level pinning at contacts causes high resistance.
Purpose of the Study:
- To enhance hole injection in WSe2 field-effect transistors (FETs).
- To overcome contact resistance issues hindering WSe2 device implementation.
- To explore a mixed-dimensional contact architecture integrating 1D edge and 2D surface contacts.
Main Methods:
- Fabrication of WSe2 FETs with a mixed-dimensional contact architecture.
- Optimization of the 1D-length/2D-area contact ratio.
- Application of ultraviolet/ozone treatment for tungsten oxide formation and hole doping.
- Characterization of device performance, including field-effect hole mobility and specific contact resistance.
Main Results:
- An optimal 1D/2D contact ratio of 0.26 yielded high field-effect hole mobility (171 cm²/V·s).
- Achieved low specific contact resistance of 2.97 kΩ·μm.
- Demonstrated a high current on/off ratio of 5 × 10⁸ and Ohmic contact behavior (Schottky barrier height of 0.09 eV).
Conclusions:
- The mixed-dimensional contact architecture effectively enhances carrier injection in WSe2 FETs.
- Ultraviolet/ozone treatment successfully reduces contact resistance via hole doping.
- This approach provides a viable strategy for high-performance, atomically thin electronic devices and TMD-based CMOS applications.
