Two-Dimensional Reconfigurable Photodiode for In-Sensor Color Filtering and Spectral Logic.

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Wavelength-selective photodetectors are crucial for advanced applications like hyperspectral imaging and secure optical communication.
• Conventional systems often require external filters or complex post-processing, increasing system size and data handling demands.

Purpose of the Study:

• To introduce a novel reconfigurable photodiode based on spatially patterned doped tungsten diselenide (WSe2).
• To demonstrate dual photodetection modes and wavelength-dependent conductance modulation for in-sensor spectral processing.

Main Methods:

• Fabrication of a spatially patterned doped tungsten diselenide (WSe2) photodiode.
• Characterization of broadband and color-filtering photodetection modes.
• Demonstration of in-sensor spectral processing, including logic operations and object recognition.
• Evaluation of performance using bias-controlled readout and convolutional neural network simulations.

Main Results:

• The device exhibits two switchable photodetection modes: broadband and color-filtering (445-780 nm).
• Broadband mode shows a fast response and a 72 dB linear dynamic range.
• Color-filtering mode enables nonvolatile, color-selective detection and in-sensor spectral processing.
• High classification accuracies (~98.99% for red, ~98.76% for green) achieved for encrypted pattern recognition.

Conclusions:

• The reconfigurable WSe2 photodiode offers a pathway to hardware-level spectral-domain information processing.
• This technology reduces system complexity and data overhead for optical sensing and communication.
• The device shows significant potential for applications requiring efficient and selective spectral analysis.