High Electron-Affinity Oxides Intercalation for p-Type Contacts in 2D Semiconductors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• van der Waals stacking of 2D materials faces challenges with low carrier injection efficiency due to weak interlayer coupling.
• Conventional doping methods like intercalation and functionalization lack control and stability, leading to performance degradation.

Purpose of the Study:

• To develop a universal, controllable, and stable doping strategy for creating efficient p-type contacts in 2D semiconductors.
• To improve carrier injection efficiency and reduce Schottky barriers in 2D electronic devices.

Main Methods:

• Employing in situ self-oxidation of 2D semimetals (e.g., 1T'-MoTe2) to form transition-metal oxide intercalations (e.g., MoO3).
• Utilizing the high electron affinity and work function of these oxides to induce p-doping in adjacent 2D semiconductors (e.g., MoS2).
• Fabricating asymmetric MoS2 Schottky diodes using the developed contact engineering approach.

Main Results:

• Achieved stable p-doping in MoS2 by forming high electron-affinity MoO3 layers.
• Significantly reduced Schottky barriers, enabling efficient carrier injection for p-type ohmic contacts.
• Demonstrated enhanced interfacial coupling through charge transfer and orbital hybridization.
• Fabricated MoS2 Schottky diodes exhibiting excellent performance.

Conclusions:

• The in situ self-oxidation strategy offers a simple, scalable, and effective method for contact engineering in 2D semiconductors.
• This approach overcomes limitations of conventional doping techniques, paving the way for high-performance 2D electronic devices.