Uncooled Mid-Infrared Sensing Enabled by Chip-Integrated Low-Temperature-Grown 2D PdTe₂ Dirac Semimetal

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Next-generation mid-infrared (MIR) imaging requires free-cooling and high integration capabilities.
• Two-dimensional (2D) semimetals offer promising infrared (IR) photoresponses but face challenges in scalable growth and on-chip integration.

Purpose of the Study:

• To demonstrate scalable, low-temperature growth of 2D semimetals for uncooled MIR sensing.
• To develop integrated MIR photodetectors and imaging arrays using 2D materials.

Main Methods:

• Utilized a low-temperature self-stitched epitaxy (SSE) approach to grow inch-level 2D palladium ditelluride (PdTe₂).
• Fabricated on-chip PdTe₂/Si Schottky junction photodetectors and integrated device arrays.
• Investigated the ultrabroadband photoresponse and imaging capabilities of the fabricated devices.

Main Results:

• Achieved inch-level continuous 2D PdTe₂ films via low-temperature SSE (∼300 °C), compatible with back-end-of-line technology.
• Demonstrated uncooled on-chip photodetectors with ultrabroadband photoresponse up to 10.6 μm and high specific detectivity.
• Showcased high-resolution room-temperature imaging capability with integrated device arrays.

Conclusions:

• The SSE method enables low-temperature, scalable growth of 2D semimetals for advanced IR applications.
• Developed functional uncooled MIR photodetectors and imaging systems for sensing and optical communication.
• Paved the way for 2D materials in uncooled MIR sensing and integrated photonic devices.