Band-hybridized selenium contact for p-type semiconductors.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Achieving low-resistance electrical contacts to p-type 2D semiconductors is challenging due to metal-induced gap states.
• While semimetals like bismuth work for n-type semiconductors, a similar solution for p-type materials is needed.
• High work function interfacial layers are crucial for reducing Schottky barrier height.

Purpose of the Study:

• To develop a novel interfacial layer for ultralow contact resistance in p-type 2D semiconductors.
• To investigate the mechanism of band hybridization at the metal-semiconductor interface.
• To demonstrate the effectiveness of the proposed method in p-type WSe2 transistors.

Main Methods:

• Introduction of an ultrathin selenium (Se) interfacial layer with a high work function.
• Formation of a band-hybridized semimetallic contact through interaction between Se and a gold electrode.
• Fabrication and characterization of p-type WSe2 field-effect transistors with the new contact.

Main Results:

• The Se interfacial layer effectively reduced the Schottky barrier height.
• Band hybridization transformed the semiconductor interface into a semimetallic one, suppressing metal-induced gap states.
• Contact resistance in p-type WSe2 transistors was reduced to 540 Ω μm.
• High ON-state current density of 430 μA μm⁻¹ was achieved with an 80-nm channel length.

Conclusions:

• The Se interfacial layer provides a scalable pathway for ultralow-resistance contacts to p-type semiconductors.
• This band-hybridized semimetallic contact strategy is transferable to other p-type materials like black phosphorus and carbon nanotubes.
• The findings enable advancements in high-performance nanoscale electronic devices.