Self-Powered Broadband Photodetection Driven by Asymmetric Surface Potential in Quasi-2D InAs Single Crystals

Area of Science:

• Materials Science
• Condensed Matter Physics
• Optoelectronics

Background:

• Two-dimensional (2D) materials offer tunable band structures and strong light-matter interactions, making them ideal for photodetectors.
• Existing photodetectors often require external bias, limiting their efficiency and portability.
• Indium arsenide (InAs) is a promising semiconductor material for optoelectronic devices.

Purpose of the Study:

• To develop high-performance, self-powered broadband photodetectors using quasi-2D InAs single crystals.
• To investigate the role of asymmetric metal-semiconductor structures in enhancing charge separation and photocurrent generation.
• To demonstrate efficient photodetection without external bias.

Main Methods:

• Growth of high-quality InAs single crystals via van der Waals epitaxy.
• Fabrication of devices with an asymmetric metal-semiconductor structure.
• Characterization of the photodetector performance, including responsivity, rise/decay times, and detectivity.
• Testing the photoresponse across a broad spectral range (300-1100 nm) at room temperature.

Main Results:

• Achieved self-powered broadband photodetection (300-1100 nm) under zero bias.
• Demonstrated high responsivity (0.6 A/W) and outstanding detectivity (2.3 × 10¹² Jones).
• Exhibited rapid response times with rise/decay times of 73.8/94 μs.
• Confirmed efficient charge separation due to the asymmetric channel in quasi-2D InAs.

Conclusions:

• The asymmetric channel in quasi-2D InAs is crucial for efficient charge separation and self-powered operation.
• This approach offers a promising route towards high-performance self-powered photodetectors (SPPDs).
• The developed InAs-based photodetectors show potential for various broadband optoelectronic applications.