Doping-Free All PtSe₂ Transistor via Thickness-Modulated Phase Transition

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Achieving high-quality metal contacts on 2D semiconductors is hindered by Fermi level pinning and lack of doping.
• Conventional methods often struggle with interface issues, limiting device performance.

Purpose of the Study:

• To demonstrate high-performance field-effect transistors (FETs) using an all-Platinum Diselenide (PtSe2) platform.
• To overcome limitations of Fermi level pinning and doping in 2D semiconductor devices.

Main Methods:

• Vertical integration of metallic thick PtSe2 source/drain onto a semiconducting ultrathin PtSe2 channel.
• Utilizing the thickness-dependent semiconductor-to-metal phase transition of PtSe2.

Main Results:

• Developed high-performance "all-PtSe2" FETs without Fermi level pinning or doping issues.
• Achieved excellent gate tunability, superior mobility, and high ON current.
• Demonstrated one order lower contact resistance compared to conventional Ti/Au contacts.

Conclusions:

• The developed PtSe2 van der Waals (vdW) contact offers a new device paradigm for 2D nanoelectronics.
• This approach overcomes a fundamental bottleneck in creating efficient contacts for 2D materials.
• Fully metallized source/drain and semiconducting channels are realized on a single PtSe2 platform.