WS₂/MHS PdTe₂/Si Mixed-Dimensional Heterojunction as Ultra-Broadband Photodetector for Health and Safety Monitoring

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Ultra-broadband photodetectors (UB-PDs) are crucial for applications in medicine and public safety.
• Existing UB-PDs face material limitations in covering the ultraviolet to medium infrared spectrum.
• Developing single-device solutions for multi-band detection remains a significant challenge.

Purpose of the Study:

• To propose and demonstrate a novel mixed-dimensional heterojunction photodetector.
• To achieve ultra-broadband detection from 365 nm to 9600 nm.
• To explore the device's potential in medical diagnostics and material differentiation.

Main Methods:

• Fabrication of a heterojunction using 2D WS₂ and monodisperse hexagonal stacking (MHS) 3D PdTe₂ nanoparticles on a 3D Si substrate.
• Characterization of photodetector performance, including responsivity, detectivity, and sensitivity.
• Demonstration of applications in blood oxygen saturation analysis and material identification.

Main Results:

• The proposed photodetector exhibits ultra-broadband detection from 365 nm to 9600 nm.
• Exceptional performance metrics achieved, including high responsivity (7.8 × 10² mA/W at 980 nm) and detectivity (2.5 × 10¹³ Jones).
• Demonstrated self-powered operation, high switching ratio (10⁴), rapid response time (24.14 µs), and photocurrent gain at zero bias.

Conclusions:

• The MHS PdTe₂/WS₂/Si heterojunction photodetector overcomes material limitations for ultra-broadband detection.
• The device shows significant potential for multifunctional applications, including medical sensing and material analysis.
• This work paves the way for advanced optoelectronic devices with extended spectral coverage.