A High-Performance In-Memory Photodetector Realized by Charge Storage in a van der Waals MISFET.

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Data-intensive applications necessitate integrated sensing, memory, and computing beyond the von Neumann architecture.
• Current photodetectors lack multifunctionality, limiting advanced optoelectronic device integration.
• The need for single-device solutions combining photodetection and data storage is growing.

Purpose of the Study:

• To propose and demonstrate a novel van der Waals heterostructure for in-memory photodetection.
• To integrate non-volatile memory capabilities directly into a photodetector device.
• To investigate the performance and underlying mechanisms of the proposed device.

Main Methods:

• Fabrication of a WSe2/h-BN van der Waals heterostructure on a Si/SiO2 substrate.
• Characterization of optoelectronic properties, including photocurrent and photoresponsivity.
• Analysis of charge-storage mechanism using in situ optoelectronic electron energy-loss spectroscopy.

Main Results:

• Achieved ultrahigh readout photocurrent (3.4 µA) and photoresponsivity (337.8 A W-1) in the solar-blind region.
• Demonstrated extended data retention time exceeding 10 years, indicating robust non-volatile memory.
• Successfully elucidated the charge-storage mechanism within the h-BN/SiO2 interface.

Conclusions:

• The developed WSe2/h-BN photodetector successfully integrates photodetection and non-volatile memory functions.
• The device exhibits excellent performance metrics and a long retention time, paving the way for advanced optoelectronics.
• The findings offer significant insights into in-memory computing architectures and device mechanisms.