Comprehensive Review on Doping Strategies for Two-Dimensional Tungsten Diselenide

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional transition metal dichalcogenides, like tungsten diselenide (WSe2), are promising for beyond-silicon electronics due to their atomic thickness and strong electrostatic control.
• WSe2 offers ambipolar transport but faces limitations like Fermi-level pinning, contact-dominated injection, and defect variability, necessitating controlled doping.

Purpose of the Study:

• To review doping strategies for WSe2 compatible with atomically thin van der Waals semiconductors.
• To analyze thermodynamic mechanisms, doping selectivity, and trade-offs in doping WSe2.
• To discuss the impact of doping on device performance and identify future challenges.

Main Methods:

• Surface charge-transfer doping using molecular adsorbates, Lewis acids, and alkali metals.
• Defect-mediated chemisorption, self-limiting oxide interfacial layers, and in situ vacancy engineering.
• Analysis of thermodynamic mechanisms, contact-selective vs. channel-selective doping, and degenerate vs. non-degenerate doping.

Main Results:

• Doping strategies effectively address Fermi-level pinning and improve carrier injection in WSe2 transistors.
• Doping enables Schottky-barrier narrowing, threshold-voltage control, and apparent mobility enhancement.
• Controlled doping has facilitated the development of complementary metal-oxide-semiconductor logic circuits using WSe2.

Conclusions:

• Controlled doping is essential for unlocking the full potential of WSe2 in next-generation electronics.
• Remaining challenges include air stability, selective-area patterning, scalable synthesis, and low-temperature integration for 3D devices.