Asymmetric electrode incorporated 2D GeSe for self-biased and efficient photodetection

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Two-dimensional (2D) layered materials offer unique electronic and optical properties.
• Germanium selenide (GeSe) is a p-type semiconductor with potential for optoelectronic applications.
• Asymmetric metal contacts are crucial for designing efficient Schottky barrier diodes (SBDs).

Purpose of the Study:

• To design and investigate a self-biased photodetector based on 2D GeSe.
• To evaluate the photoresponse of the GeSe photodetector across various wavelengths.
• To assess the device's performance metrics for photodetection applications.

Main Methods:

• Fabrication of a photodetector using p-type 2D GeSe with asymmetric Cr/Au and Pd/Au electrodes.
• Measurement of photoresponse under photovoltaic effect for wavelengths ~220, ~530, and ~850 nm.
• Characterization of device performance including responsivity, detectivity, and response time.

Main Results:

• The GeSe photodetector demonstrated efficient photodetection under photovoltaic mode.
• The device exhibited high sensitivity to near-infrared (NIR) light (~850 nm) at zero bias.
• Key performance metrics include responsivity (280 mA/W), detectivity (4.1 × 10^9 Jones), and a response time of 69 ms for 850 nm light.

Conclusions:

• The developed GeSe photodetector is a promising candidate for self-biased optoelectronic applications.
• The device's sensitivity to NIR light makes it suitable for emergency applications like fire detection and night vision.
• 2D GeSe shows potential as a novel material for Schottky barrier diode optoelectronics.