Self-powered In₂Se₃/Ge photodetector from a visible to short-wave infrared region

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Developing broadband photodetectors is crucial for advanced optical sensing and communication.
• Indium Selenide (In2Se3) and Germanium (Ge) are promising semiconductor materials for optoelectronic devices.

Purpose of the Study:

• To fabricate and characterize an In2Se3/Ge heterojunction photodetector.
• To evaluate its performance across a broad spectral range, including visible and short-wave infrared regions.
• To explore its potential applications in optical communication.

Main Methods:

• Fabrication of the In2Se3/Ge heterojunction using molecular beam epitaxy.
• Characterization of the photodetector's spectral response, responsivity, specific detectivity, and response time.
• Testing the device's performance at zero bias (self-powered operation).

Main Results:

• The In2Se3/Ge heterojunction exhibits a broad photosensitive spectrum from 400 nm to 1700 nm.
• Achieved self-powered high responsivity (0.32 A/W at 450 nm, 0.52 A/W at 1550 nm) and specific detectivity (3.2 x 10^11 Jones at 450 nm, 5.2 x 10^11 Jones at 1550 nm) at zero bias.
• Demonstrated a fast response speed with sub-millisecond response time.
• The device shows a superposable dual-band photoresponse.

Conclusions:

• The high quality of the In2Se3-Ge interface is key to the device's excellent performance.
• The In2Se3/Ge photodetector is a promising candidate for self-powered, broadband detection.
• The demonstrated capabilities highlight its potential for applications such as encrypted optical communication.