All-Optical Modulation Photodetectors Based on the CdS/Graphene/Ge Sandwich Structures for Integrated...

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• All-optical modulation photodetectors are crucial for high-speed communication and computing.
• Graphene's unique electronic properties offer potential for advanced photodetector designs.
• Tuning photodetector response is essential for versatile applications.

Purpose of the Study:

• To design and investigate an all-optical modulation photodetector based on a CdS/graphene/Ge sandwich structure.
• To explore the device's ability to tune visible light response speed and responsivity.
• To demonstrate the potential for all-optical encrypted communication and neuromorphic hardware.

Main Methods:

• Fabrication of a CdS/graphene/Ge sandwich structure photodetector.
• Utilizing near-infrared modulation light to alter the graphene channel's Fermi level.
• Analyzing the device's photoresponse under varying modulation light conditions.
• Performing logical operations using superimposed signal and modulation light.

Main Results:

• Achieved tunable visible light response speed and a broad responsivity range (negative to positive).
• Demonstrated all-optical control over the photodetector's response by adjusting modulation light power.
• Confirmed the device's capability to perform logical operations for encrypted communication.
• Showcased ultrahigh tunability and symmetric positive/negative photoconductivity.

Conclusions:

• The designed all-optical modulation photodetector offers significant advantages for high-speed encrypted communication and neuromorphic hardware.
• The device's tunability and photoconductivity enhance computational capacity and fault tolerance in integrated sensing-computing (ISC).
• This work provides insights for developing next-generation high-bandwidth, low-power-consumption ISC devices.