Structural and Electric Characterization of Sputtered Pt/WSe₂ Contacts toward High-Performance 2D p‑FETs.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• High-performance p-type field-effect transistors (FETs) utilize two-dimensional (2D) materials for efficient hole injection.
• Platinum (Pt) is a high work function metal advantageous for p-type contacts but its sputtering damages delicate 2D materials.
• Previous studies showed sputtering can create van der Waals contacts in Sb2Te3/MoS2, motivating further investigation.

Purpose of the Study:

• To investigate the performance of tungsten diselenide (WSe2) p-FETs using sputtered Pt electrodes.
• To analyze the structural integrity of WSe2 after Pt deposition via sputtering.
• To systematically examine the relationship between deposition methods, materials, and damage extent in 2D FET fabrication.

Main Methods:

• Fabrication of WSe2 p-FETs with sputtered Pt electrodes.
• Electrical characterization of fabricated devices, including monolayer WSe2.
• Structural analysis using various characterization techniques to assess WSe2 crystal integrity.
• Systematic examination of sputtering applicability and material-dependent damage.

Main Results:

• Reasonable p-FET performance was achieved with sputtered Pt electrodes, even in monolayer WSe2.
• Structural characterization revealed significant damage to the WSe2 crystal structure post-sputtering.
• Evidence suggests the formation of quasi-edge contacts between the Pt-sputtered WSe2 and the WSe2 channel.
• The study explored the correlation between deposition techniques, materials, and the degree of structural damage.

Conclusions:

• Sputtered Pt electrodes on WSe2 lead to device performance but compromise the material's structural integrity.
• The formation of quasi-edge contacts is a key consequence of the high-energy Pt sputtering process on WSe2.
• Understanding and mitigating sputtering-induced damage is crucial for optimizing 2D material-based electronic devices.