On-Chip Full-UV-Band Photodetectors Enabled by Hot Hole Extraction

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Traditional UV photodetectors face challenges in full-band detection and require high operating voltages.
• Limitations in material properties restrict the detection range and efficiency of existing UV sensors.

Purpose of the Study:

• To develop a self-driven, on-chip photodetector capable of full-UV band detection (UV-A, UV-B, UV-C).
• To overcome limitations of narrow detection ranges and high operating voltages in conventional UV detectors.

Main Methods:

• Fabrication of a heterostructure device using hybrid gold nanoislands (Au NIs) embedded in H-glass and cesium bismuth iodide (Cs3Bi2I9).
• Utilizing Au NIs as nucleation sites to enhance Cs3Bi2I9 crystallinity and vertical alignment.
• Leveraging the built-in electric field at the heterojunction for efficient hot hole separation and charge transfer.

Main Results:

• The photodetector demonstrated an ultrahigh open-circuit voltage of 0.6 V and a responsivity of 0.88 A/W.
• Achieved a low detection threshold of 90 nW/cm2, outperforming existing thin-film UV photodetectors in self-driven mode.
• Exhibited robust operational reliability with long-term stability for up to eight months under ambient conditions.

Conclusions:

• The developed heterostructure architecture enables efficient hot hole dynamics for self-driven, full-UV band photodetection.
• This advancement offers promising applications in environmental monitoring, flame detection, biomedical diagnostics, and secure communication.