Polarimetric Image Sensor and Fermi Level Shifting Induced Multichannel Transition Based on 2D PdPS

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials offer unique properties like low symmetry and high stability.
• Current 2D photodetectors are limited by narrow spectral responses.
• Achieving wide spectral response requires precise bandgap engineering and Fermi level regulation.

Purpose of the Study:

• To design and synthesize a novel 2D material for broad spectral response photodetectors.
• To investigate the optoelectrical and polarization detection properties of the new material.
• To demonstrate the potential for polarimetric imaging and hidden-target detection.

Main Methods:

• Design and synthesis of palladium phosphide sulfide (PdPS) 2D material.
• Characterization of PdPS bandgap and Fermi level modulation via defects (S vacancies, interstitial Pd/P).
• Fabrication and testing of PdPS-based photodetectors for spectral response, photoresponsivity, detectivity, and polarization sensitivity.

Main Results:

• PdPS exhibits a bandgap of ~2.1 eV, with defects tuning the Fermi level near the conduction band.
• The PdPS photodetector demonstrates a wide spectral response from solar-blind UV to near-infrared.
• Superior optoelectrical performance achieved: photoresponsivity (R) of 1 × 10^3 A/W and detectivity (D*) of 4 × 10^11 Jones at 532 nm.
• Good polarization detection with a dichroic ratio of ~3.7 at 808 nm.

Conclusions:

• PdPS is a promising noble 2D material for advanced photodetectors.
• The multichannel transition mechanism enables a wide spectral response.
• PdPS shows significant potential for polarimetric imaging and active detection applications.