Ultrasensitive photoelectric detection with room temperature extremum

Area of Science:

• Condensed Matter Physics
• Materials Science
• Optoelectronics

Background:

• Room-temperature photodetection is crucial for applications like sensing, imaging, and telecommunications.
• Existing photodetectors lack the extreme sensitivity required for advanced room-temperature applications.
• The development of novel materials and phenomena is needed to overcome current limitations.

Purpose of the Study:

• To explore the potential of tantalum nickel selenide (Ta2NiSe5) for highly sensitive room-temperature photodetection.
• To investigate the role of the excitonic insulator phase transition in enhancing photoelectric response.
• To develop optimized photodetector devices for broad wavelength applications.

Main Methods:

• Investigated the photoelectric response of tantalum nickel selenide (Ta2NiSe5) across visible to terahertz spectra.
• Fabricated a photoconductive detector based on Ta2NiSe5 to measure sensitivity and bandwidth.
• Constructed a van der Waals heterostructure (Ta2NiSe5/WS2) to improve dark current suppression and ambient performance.

Main Results:

• Observed distinct peaks in photoelectric response attributed to the anomalous excitonic insulator phase transition in Ta2NiSe5.
• Achieved an extreme sensitivity (specific detectivity D* of 5.3 × 10^11 cm·Hz^1/2·W^-1) and 360 kHz bandwidth in the terahertz range.
• The Ta2NiSe5/WS2 heterostructure demonstrated significantly improved ambient detectivity (D* of 4.1 × 10^12 cm·Hz^1/2·W^-1) in the visible range.

Conclusions:

• The excitonic insulator phase transition in Ta2NiSe5 enables unprecedented room-temperature photodetection sensitivity.
• Ta2NiSe5-based devices offer superior performance for both visible and terahertz detection compared to state-of-the-art technologies.
• This research opens new avenues for optoelectronics and sensitive remote sensing applications at room temperature.